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| 119 | </style></head>
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| 120 | <body>
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| 121 | <div class="body">
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| 122 | <p style="text-align: center; background: #ccc; border: 1px solid #2d5588;"><a
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| 123 | style="text-decoration: none;"
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| 124 | href="http://www.la-samhna.de/samhain/">samhain file integrity
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| 125 | scanner</a> | <a style="text-decoration: none;"
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| 126 | href="http://www.la-samhna.de/samhain/s_documentation.html">online
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| 127 | documentation</a></p>
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| 128 | <br><center><h1><a name="FAQ-top">Frequently Asked Questions for Samhain</a></h1></center>
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| 129 | <br><center><h2>Rainer Wichmann</h2></center>
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| 130 | <hr>
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| 131 | <p><i>FAQ Revised: Saturday 17 September 2005 09:10:07</i></p>
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| 132 | <hr><h2>Table of Contents</h2>
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| 133 | <dl>
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| 134 | <dt><b>1. Most frequently</b></dt>
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| 135 | <dd><ul>
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| 136 | <li><a href="#Most frequently0">1.1. Owner not trustworthy / Group writeable and member not trustworthy</a></li>
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| 137 | <li><a href="#Most frequently1">1.2. samhain exits with the message "Untrusted path" for config/log/pid/database files</a></li>
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| 138 | <li><a href="#Most frequently2">1.3. It does not log anything / Can't stop logging to console</a></li>
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| 139 | <li><a href="#Most frequently3">1.4. Client cannot self-resolve, but nslookup works fine</a></li>
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| 140 | </ul></dd>
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| 141 | <dt><b>2. Build and install</b></dt>
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| 142 | <dd><ul>
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| 143 | <li><a href="#Build and install0">2.1. [Fedora Core] Cannot compile with --enable-khide</a></li>
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| 144 | <li><a href="#Build and install1">2.2. [Fedora Core] Cannot compile with --with-kcheck</a></li>
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| 145 | <li><a href="#Build and install2">2.3. "make" loops infinitely !</a></li>
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| 146 | <li><a href="#Build and install3">2.4. Why does static compiling (<code>--enable-static</code>) on Solaris fail ?</a></li>
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| 147 | <li><a href="#Build and install4">2.5. Compilation fails with '/usr/bin/ld: cannot find -lnss_files'</a></li>
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| 148 | <li><a href="#Build and install5">2.6. The executable is corrupted after installation</a></li>
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| 149 | <li><a href="#Build and install6">2.7. --enable-xml-log has no effect</a></li>
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| 150 | <li><a href="#Build and install7">2.8. ./install-sh: strip: not found (Solaris)</a></li>
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| 151 | </ul></dd>
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| 152 | <dt><b>3. File checking</b></dt>
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| 153 | <dd><ul>
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| 154 | <li><a href="#File checking0">3.1. How can I exclude a (sub-)directory ?</a></li>
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| 155 | <li><a href="#File checking1">3.2. In messages about policy violations, what does the code after POLICY [XYZ]
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| 156 | mean ?</a></li>
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| 157 | <li><a href="#File checking2">3.3. Does samhain support prelink ?</a></li>
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| 158 | <li><a href="#File checking3">3.4. I get error messages about 'subdirectory count != hardlinks'</a></li>
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| 159 | </ul></dd>
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| 160 | <dt><b>4. Client/Server</b></dt>
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| 161 | <dd><ul>
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| 162 | <li><a href="#Client/Server0">4.1. I don't want to poke a hole into my firewall to let the client connect to the server !</a></li>
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| 163 | <li><a href="#Client/Server1">4.2. The client sends 127.0.0.1 (or some other numerical address) as its name to the log server</a></li>
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| 164 | <li><a href="#Client/Server2">4.3. The server wants to send rc.ip-adress rather than rc.fqdn to the client</a></li>
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| 165 | <li><a href="#Client/Server3">4.4. Cannot resolve client name host=XXX</a></li>
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| 166 | <li><a href="#Client/Server4">4.5. Cannot resolve socket peer IP for client host=XXX peer=YYY</a></li>
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| 167 | <li><a href="#Client/Server5">4.6. Reverse lookup of socket peer failed host=XXX peer=YYY obj=ZZZ</a></li>
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| 168 | <li><a href="#Client/Server6">4.7. No socket peer alias matches client name host=XXX peer=YYY</a></li>
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| 169 | <li><a href="#Client/Server7">4.8. Session key negotiation failed</a></li>
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| 170 | <li><a href="#Client/Server8">4.9. Invalid connection attempt: Not in client list</a></li>
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| 171 | <li><a href="#Client/Server9">4.10. Invalid connection attempt: Session key mismatch</a></li>
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| 172 | <li><a href="#Client/Server10">4.11. How do I update the file signature database ?</a></li>
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| 173 | <li><a href="#Client/Server11">4.12. Time limit exceeded</a></li>
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| 174 | <li><a href="#Client/Server12">4.13. Invalid connection attempt: Signature mismatch</a></li>
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| 175 | <li><a href="#Client/Server13">4.14. [Server] PANIC .. Address already in use subroutine=bind</a></li>
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| 176 | </ul></dd>
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| 177 | <dt><b>5. Email</b></dt>
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| 178 | <dd><ul>
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| 179 | <li><a href="#Email0">5.1. Reverse lookup failed</a></li>
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| 180 | <li><a href="#Email1">5.2. From daemon@example.com</a></li>
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| 181 | <li><a href="#Email2">5.3. How do I define more than one email addresses ?</a></li>
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| 182 | </ul></dd>
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| 183 | <dt><b>6. Misc</b></dt>
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| 184 | <dd><ul>
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| 185 | <li><a href="#Misc0">6.1. Error message: "Invalid line XYZ in configuration file"</a></li>
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| 186 | <li><a href="#Misc1">6.2. Why do I get a local logfile if I log to the server ?</a></li>
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| 187 | <li><a href="#Misc2">6.3. Why is there no NIS support with a static samhain executable on Linux ?</a></li>
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| 188 | <li><a href="#Misc3">6.4. Why do I get hundreds of messages about modified CTIME ?</a></li>
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| 189 | <li><a href="#Misc4">6.5. PANIC — File not accessible</a></li>
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| 190 | <li><a href="#Misc5">6.6. How can I avoid error messages for invalid UIDs (no such user) ?</a></li>
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| 191 | <li><a href="#Misc6">6.7. [Redhat] The /etc/init.d/(samhain|yule) init script hangs</a></li>
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| 192 | <li><a href="#Misc7">6.8. The /etc/init.d/(samhain|yule) init script exits with: execvp: No such file or directory</a></li>
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| 193 | <li><a href="#Misc8">6.9. Why am I not receiving the "BEGIN LOGKEY" message by email ?</a></li>
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| 194 | <li><a href="#Misc9">6.10. Why does console logging fail if I compile with
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| 195 | <code>--enable-(micro-)stealth</code> ?</a></li>
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| 196 | <li><a href="#Misc10">6.11. I need a list for my schedule !</a></li>
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| 197 | <li><a href="#Misc11">6.12. The hiding kernel module has no effect !</a></li>
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| 198 | <li><a href="#Misc12">6.13. What does the message "Large lstat/open overhead" mean ?</a></li>
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| 199 | <li><a href="#Misc13">6.14. What does the message "Device not available path=/dev/random" mean ? I have /dev/random !</a></li>
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| 200 | <li><a href="#Misc14">6.15. Logging to an external program fails; the program receives no data
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| 201 | on stdin !</a></li>
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| 202 | <li><a href="#Misc15">6.16. SIGILL on AIX</a></li>
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| 203 | </ul></dd>
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| 204 | <dt><b>7. Database</b></dt>
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| 205 | <dd><ul>
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| 206 | <li><a href="#Database0">7.1. Why are client messages corrupted / incompletely stored in the DB ?</a></li>
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| 207 | <li><a href="#Database1">7.2. I want / don't want the server timestamps (for client messages) in the SQL database</a></li>
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| 208 | <li><a href="#Database2">7.3. I don't want the client TIMESTAMP messages in the SQL database</a></li>
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| 209 | <li><a href="#Database3">7.4. What does the log_ref field mean ?</a></li>
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| 210 | </ul></dd>
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| 211 | </dl>
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| 212 | <hr><h2>1. Most frequently</h2>
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| 213 | <dl>
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| 214 | <dt><b><a name="Most frequently0">1.1. Owner not trustworthy / Group writeable and member not trustworthy</a></b></dt>
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| 215 | <dd>An untrusted user (might be an untrusted group member
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| 216 | for group writeable files/directories) owns or can write to an
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| 217 | element in the path listed in the error message. This concerns
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| 218 | the configuration file, the log file, and the database file.
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| 219 | The offending element in the path is identified as obj=/xxx in the
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| 220 | error message.
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| 221 | To fix the problem, see next entry.<br><br></dd>
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| 222 | <dt><b><a name="Most frequently1">1.2. samhain exits with the message "Untrusted path" for config/log/pid/database files</a></b></dt>
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| 223 | <dd>Paths to critical
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| 224 | files (e.g. the configuration file) must be writeable by trusted users
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| 225 | only.
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| 226 | If a path element is group writeable, all group members must be trusted.
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| 227 | By default, only <i>root</i> and the (effective) <i>user</i> of
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| 228 | the program are trusted. To add trusted users, use the compile time
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| 229 | option
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| 230 | <div class="block"><pre>
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| 231 | $ ./configure --with-trusted=0,...
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| 232 | </pre></div>
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| 233 | or the configure file option:
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| 234 | <div class="block"><pre>
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| 235 | [Misc]
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| 236 | TrustedUser=username
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| 237 | </pre></div>
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| 238 | If the path to the configuration file itself is writeable
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| 239 | by other users than <i>root</i> and the
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| 240 | <i>effective user</i>
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| 241 | these must be defined as trusted already
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| 242 | at compile time.<br><br></dd>
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| 243 | <dt><b><a name="Most frequently2">1.3. It does not log anything / Can't stop logging to console</a></b></dt>
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| 244 | <dd>(1) There is a section in the manual dealing with
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| 245 | logging and filtering.<br />
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| 246 |
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| 247 | (2) To log to the console:
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| 248 | <div class="block"><pre>
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| 249 | $ samhain -p info ...
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| 250 | </pre></div>
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| 251 | or in the configuration file:
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| 252 | <div class="block"><pre>
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| 253 | [Log]
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| 254 | PrintSeverity=info
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| 255 | </pre></div>
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| 256 |
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| 257 | To <i>stop</i> logging to the console:
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| 258 | <div class="block"><pre>
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| 259 | $ samhain -p none ...
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| 260 | </pre></div>
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| 261 | or in the configuration file:
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| 262 | <div class="block"><pre>
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| 263 | [Log]
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| 264 | PrintSeverity=none
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| 265 | </pre></div>
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| 266 | Defining <tt>/dev/null</tt> as console device works as well, but
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| 267 | is a bad idea, because samhain will open the device and write (i.e. it is
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| 268 | a very inefficient method).<br><br></dd>
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| 269 | <dt><b><a name="Most frequently3">1.4. Client cannot self-resolve, but nslookup works fine</a></b></dt>
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| 270 | <dd><ul>
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| 271 | <li>Nslookup is a program to query Internet domain name servers.
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| 272 | </li>
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| 273 | <li>Applications (like samhain) are not supposed to query DNS servers
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| 274 | directly. Rather, they are supposed to query the resolver library that:
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| 275 | <ul>
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| 276 | <li>is provided by the operating system,</li>
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| 277 | <li>configured by the system administrator,</li>
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| 278 | <li>may use several different method to determine host names, as
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| 279 | configured in <tt>/etc/nsswitch.conf</tt>, and</li>
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| 280 | <li>usually is configured to give precedence to
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| 281 | the <tt>/etc/hosts</tt> file.</li>
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| 282 | </ul>
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| 283 | </li>
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| 284 | <li>Therefore, whether nslookup gives correct answers may be completely
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| 285 | irrelevant. For self-resolving the own hostname, the resolver
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| 286 | library probably will use <tt>/etc/hosts</tt>, rather than
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| 287 | querying a DNS server.
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| 288 | </li>
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| 289 | </ul>
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| 290 | <p>
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| 291 | Below you can find some examples of good and bad <tt>/etc/hosts</tt> files:
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| 292 | </p>
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| 293 | <div class="block"><pre>
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| 294 | # CORRECT
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| 295 | #
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| 296 | 127.0.0.1 localhost
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| 297 | xxx.xxx.xxx.xxx myhost.mydomain.tld myhost
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| 298 | </pre></div>
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| 299 |
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| 300 | <div class="block"><pre>
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| 301 | # CORRECT
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| 302 | #
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| 303 | 127.0.0.1 localhost.localdomain localhost
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| 304 | xxx.xxx.xxx.xxx myhost.mydomain.tld myhost
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| 305 | </pre></div>
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| 306 |
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| 307 | <div class="block"><pre>
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| 308 | # BAD
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| 309 | #
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| 310 | 127.0.0.1 myhost.mydomain.tld localhost
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| 311 | xxx.xxx.xxx.xxx myhost.mydomain.tld myhost
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| 312 | </pre></div>
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| 313 |
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| 314 | <div class="block"><pre>
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| 315 | # BAD
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| 316 | #
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| 317 | 127.0.0.1 localhost myhost
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| 318 | xxx.xxx.xxx.xxx myhost.mydomain.tld myhost
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| 319 | </pre></div><br><br></dd>
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| 320 | </dl>
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| 321 | <hr><h2>2. Build and install</h2>
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| 322 | <dl>
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| 323 | <dt><b><a name="Build and install0">2.1. [Fedora Core] Cannot compile with --enable-khide</a></b></dt>
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| 324 | <dd>The Fedora Core kernel is patched to unconditionally deny reading
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| 325 | from /dev/kmem. Compiling the stealth kernel modules is not possible
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| 326 | under these circumstances.<br><br></dd>
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| 327 | <dt><b><a name="Build and install1">2.2. [Fedora Core] Cannot compile with --with-kcheck</a></b></dt>
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| 328 | <dd>The Fedora Core kernel is patched to unconditionally deny reading
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| 329 | from /dev/kmem. Checking the kernel for the presence of rootkits is
|
|---|
| 330 | not possible under these circumstances.<br><br></dd>
|
|---|
| 331 | <dt><b><a name="Build and install2">2.3. "make" loops infinitely !</a></b></dt>
|
|---|
| 332 | <dd>This may happen (e.g. when building via NFS for multiple architectures)
|
|---|
| 333 | if the relative timestamps in the source directory are
|
|---|
| 334 | wrong (time not in sync on different machines) or some intermediate
|
|---|
| 335 | target is unusable (up-to-date, but built for a different OS). Use
|
|---|
| 336 | "touch * && make distclean" in the source directory
|
|---|
| 337 | to recover.<br><br></dd>
|
|---|
| 338 | <dt><b><a name="Build and install3">2.4. Why does static compiling (<code>--enable-static</code>) on Solaris fail ?</a></b></dt>
|
|---|
| 339 | <dd>Ingo Rogalsky has provided the following information: It isn't possible
|
|---|
| 340 | to link Samhain statically with Solaris. This
|
|---|
| 341 | is a Solaris issue (see Sun Infodoc ID12624) and not a samhain problem.<br><br></dd>
|
|---|
| 342 | <dt><b><a name="Build and install4">2.5. Compilation fails with '/usr/bin/ld: cannot find -lnss_files'</a></b></dt>
|
|---|
| 343 | <dd>For Linux, this is a known problem with --enable-static if you compile
|
|---|
| 344 | in MySQL support. The problem is that the
|
|---|
| 345 | <tt>mysql_config</tt> that comes as part of the MySQL
|
|---|
| 346 | distribution script incorrectly lists dependencies on
|
|---|
| 347 | the libnss_files and libnss_dns libraries which are only available as
|
|---|
| 348 | shared libraries, so the linker cannot find the static libraries.
|
|---|
| 349 |
|
|---|
| 350 | You can check this by inspecting the output of
|
|---|
| 351 | <code>mysql_config --libs</code>. The version of
|
|---|
| 352 | <tt>mysql_config</tt> that comes with the RedHat mysql
|
|---|
| 353 | RPM (RedHat 9) does not have this bug; the one distributed by the MySQL
|
|---|
| 354 | people has. You can fix the problem by editing
|
|---|
| 355 | <tt>mysql_config</tt>: search for the
|
|---|
| 356 | <i>client_libs</i> variable, and remove all instances
|
|---|
| 357 | of <i>-lnss_files</i> and <i>-lnss_dns</i>.<br><br></dd>
|
|---|
| 358 | <dt><b><a name="Build and install5">2.6. The executable is corrupted after installation</a></b></dt>
|
|---|
| 359 | <dd>The executable will get stripped during the installation. On
|
|---|
| 360 | suitable systems (i386 Linux/FreeBSD currently), additionally
|
|---|
| 361 | the "sstrip"
|
|---|
| 362 | utility (copyright 1999 by Brian Raiter, under the GNU GPL)
|
|---|
| 363 | will be used to strip the executable even more, to prevent
|
|---|
| 364 | debugging with the GNU "gdb" debugger.
|
|---|
| 365 | The "strip" utility cannot handle the resulting
|
|---|
| 366 | executable, therefore trying to strip manually after installation
|
|---|
| 367 | will corrupt the executable.<br><br></dd>
|
|---|
| 368 | <dt><b><a name="Build and install6">2.7. --enable-xml-log has no effect</a></b></dt>
|
|---|
| 369 | <dd>If you have compiled for stealth, you won't see much, because if
|
|---|
| 370 | obfuscated, then both a 'normal' and an XML logfile look,
|
|---|
| 371 | well ... obfuscated. Use <code>samhain -jL /path/to/logfile</code>
|
|---|
| 372 | to view the logfile.<br><br></dd>
|
|---|
| 373 | <dt><b><a name="Build and install7">2.8. ./install-sh: strip: not found (Solaris)</a></b></dt>
|
|---|
| 374 | <dd>Install the SUNWbtool package.<br><br></dd>
|
|---|
| 375 | </dl>
|
|---|
| 376 | <hr><h2>3. File checking</h2>
|
|---|
| 377 | <dl>
|
|---|
| 378 | <dt><b><a name="File checking0">3.1. How can I exclude a (sub-)directory ?</a></b></dt>
|
|---|
| 379 | <dd><div class="block"><pre>
|
|---|
| 380 | [IgnoreAll]
|
|---|
| 381 | dir=-1/ignore/this/subdirectory
|
|---|
| 382 | </pre></div><br><br></dd>
|
|---|
| 383 | <dt><b><a name="File checking1">3.2. In messages about policy violations, what does the code after POLICY [XYZ]
|
|---|
| 384 | mean ?</a></b></dt>
|
|---|
| 385 | <dd>This code indicates which items are modified (e.g. C = checksum). You can
|
|---|
| 386 | find a description in section 5.4.9 in the user manual. It is there because
|
|---|
| 387 | then you can see in the message list of the Beltane web console what has been
|
|---|
| 388 | modified, without the need to look at the message in detail.<br><br></dd>
|
|---|
| 389 | <dt><b><a name="File checking2">3.3. Does samhain support prelink ?</a></b></dt>
|
|---|
| 390 | <dd>Yes. There is a special checking policy [Prelink]. Directories with
|
|---|
| 391 | prelinked executables / shared libraries (see /etc/prelink.conf) should be
|
|---|
| 392 | placed under this policy, rather than under the [ReadOnly] policy.<br><br></dd>
|
|---|
| 393 | <dt><b><a name="File checking3">3.4. I get error messages about 'subdirectory count != hardlinks'</a></b></dt>
|
|---|
| 394 | <dd>Some filesystems do not always follow the rule that the number
|
|---|
| 395 | of directory
|
|---|
| 396 | hardlinks equals the number of subdirectories. E.g. the root directory of
|
|---|
| 397 | reiserfs partitions generally seems to have two additional hardlinks.
|
|---|
| 398 | To account for such exceptions, you can either switch off the
|
|---|
| 399 | hardlink check globally, or specify exceptions:
|
|---|
| 400 | <div class="block"><pre>
|
|---|
| 401 | [Misc]
|
|---|
| 402 | # Switch off hardlink check
|
|---|
| 403 | #
|
|---|
| 404 | UseHardlinkCheck=no
|
|---|
| 405 | </pre></div>
|
|---|
| 406 | <div class="block"><pre>
|
|---|
| 407 | [Misc]
|
|---|
| 408 | # Specify exceptions for the hardlink check
|
|---|
| 409 | #
|
|---|
| 410 | HardlinkOffset=N:/path
|
|---|
| 411 | </pre></div>
|
|---|
| 412 | Here, N is the numerical offset (actual - expected hardlinks) for
|
|---|
| 413 | '/path'. For multiple exceptions, use
|
|---|
| 414 | this options multiple times (note that '/path N:/path2' would itself be a valid
|
|---|
| 415 | path, so using the option only once with multiple exceptions on the same line
|
|---|
| 416 | would be ambiguous).<br><br></dd>
|
|---|
| 417 | </dl>
|
|---|
| 418 | <hr><h2>4. Client/Server</h2>
|
|---|
| 419 | <dl>
|
|---|
| 420 | <dt><b><a name="Client/Server0">4.1. I don't want to poke a hole into my firewall to let the client connect to the server !</a></b></dt>
|
|---|
| 421 | <dd>Pat Smith has posted the following solution. On the client, create
|
|---|
| 422 | an iptable rule as follows (<i>note: you probably don't need this if you
|
|---|
| 423 | configure / compile in 127.0.0.1 as the server address</i>):
|
|---|
| 424 | <div class="block"><pre>
|
|---|
| 425 | iptables -t nat -A OUTPUT -p tcp -m tcp --dport 49777 -d <i>server-ip</i> -j REDIRECT
|
|---|
| 426 | </pre></div>
|
|---|
| 427 |
|
|---|
| 428 | On the server, create an ssh tunnel for each client outside the firewall:
|
|---|
| 429 |
|
|---|
| 430 | <div class="block"><pre>
|
|---|
| 431 | ssh -f -C -R 49777:localhost:49777 -N <i>client-ip</i>
|
|---|
| 432 | </pre></div>
|
|---|
| 433 |
|
|---|
| 434 | It is necessary that each client has a distinct name, and that the server
|
|---|
| 435 | knows the name of the client. With the setup above, each client will appear
|
|---|
| 436 | as "localhost" to the server, thus the server
|
|---|
| 437 | needs to trust the client name
|
|---|
| 438 | as reported by the client itself, and suppress all eroors on resolving
|
|---|
| 439 | this name to the apparent address. In the server configuration:
|
|---|
| 440 |
|
|---|
| 441 | <div class="block"><pre>
|
|---|
| 442 | [Misc]
|
|---|
| 443 | SetClientFromAccept = false
|
|---|
| 444 | SeverityLookup = debug
|
|---|
| 445 | </pre></div>
|
|---|
| 446 |
|
|---|
| 447 | Obviously, self-resolving must work on the client machine, otherwise
|
|---|
| 448 | you are in trouble (see next issue).<br><br></dd>
|
|---|
| 449 | <dt><b><a name="Client/Server1">4.2. The client sends 127.0.0.1 (or some other numerical address) as its name to the log server</a></b></dt>
|
|---|
| 450 | <dd>See 'Client cannot self-resolve' in the 'Most frequently' section<br><br></dd>
|
|---|
| 451 | <dt><b><a name="Client/Server2">4.3. The server wants to send rc.ip-adress rather than rc.fqdn to the client</a></b></dt>
|
|---|
| 452 | <dd>The client self-resolves to its ip address.
|
|---|
| 453 | See 'Client cannot self-resolve' in the 'Most frequently' section<br><br></dd>
|
|---|
| 454 | <dt><b><a name="Client/Server3">4.4. Cannot resolve client name host=XXX</a></b></dt>
|
|---|
| 455 | <dd><div class="block"><pre>
|
|---|
| 456 | The server must be able to determine the client name.
|
|---|
| 457 | This is because only authenticated connections from registered
|
|---|
| 458 | clients are allowed, and
|
|---|
| 459 | the server must be able to check the client hostname against the list of
|
|---|
| 460 | allowed hosts, and look up the password verifier for that
|
|---|
| 461 | host.
|
|---|
| 462 | </pre></div>
|
|---|
| 463 | There are two different ways to accomplish this. Unfortunately, judging
|
|---|
| 464 | from customer feedback as well from common sense, both do not work very well
|
|---|
| 465 | with a messed up local DNS (including /etc/hosts files) and/or
|
|---|
| 466 | überparanoid or misconfigured firewalls (in case of connections
|
|---|
| 467 | across one).
|
|---|
| 468 | <ul>
|
|---|
| 469 | <li>
|
|---|
| 470 | <p>
|
|---|
| 471 | <i>First method: Determine client name on client, and
|
|---|
| 472 | try to cross-check on server</i>
|
|---|
| 473 | <p>
|
|---|
| 474 | <p>
|
|---|
| 475 | This does not work for a number of people because (1) the
|
|---|
| 476 | <tt>/etc/hosts</tt> file on the client machine has errors
|
|---|
| 477 | (yes, there are plenty machines with a completely
|
|---|
| 478 | messed up <tt>/etc/hosts</tt> file), (2) the
|
|---|
| 479 | server cannot resolve the client address because the local DNS is
|
|---|
| 480 | f***ed up, or (3) the client machine has multiple network interfaces, and
|
|---|
| 481 | the interface used is not the one the client name resolves to.
|
|---|
| 482 | </p>
|
|---|
| 483 | <p>
|
|---|
| 484 | If the client uses the wrong interface on a multi-interface machine,
|
|---|
| 485 | there is a config file option
|
|---|
| 486 | <tt>SetBindAddress=</tt><i>IP address</i>
|
|---|
| 487 | that allows to choose the interface the client will use for
|
|---|
| 488 | outgoing connections.
|
|---|
| 489 | </p>
|
|---|
| 490 | <p>
|
|---|
| 491 | If you want to download the config file from the server, you
|
|---|
| 492 | should instead use the corresponding command line
|
|---|
| 493 | <tt>--bind-address=</tt><i>IP address</i>
|
|---|
| 494 | to select the interface.
|
|---|
| 495 | </p>
|
|---|
| 496 |
|
|---|
| 497 | <p>
|
|---|
| 498 | If you encounter problems, you may (1) fix your
|
|---|
| 499 | <tt>/etc/hosts</tt> file(s), (2) fix your local DNS, or
|
|---|
| 500 | (3) switch to the second method.
|
|---|
| 501 | </p>
|
|---|
| 502 | <p>
|
|---|
| 503 | Errors in name resolving/cross-checking can be avoided by setting a
|
|---|
| 504 | very low severity (lower than the logging threshold), e.g.
|
|---|
| 505 | </p>
|
|---|
| 506 | <p>
|
|---|
| 507 | <tt>SeverityLookup=</tt><i>debug</i>
|
|---|
| 508 | </p>
|
|---|
| 509 | <p>
|
|---|
| 510 | in the <i>Misc</i> section of the server configuration,
|
|---|
| 511 | if you prefer running <i>unsafe</i> at any speed
|
|---|
| 512 | instead of fixing the problem (you have been warned). Doing so will
|
|---|
| 513 | allow an attacker to pose as the client.
|
|---|
| 514 | </p>
|
|---|
| 515 | </li>
|
|---|
| 516 | <li>
|
|---|
| 517 | <p><i>Second method: Use address of connecting entity as
|
|---|
| 518 | known to the communication layer</i></p>
|
|---|
| 519 | <p>
|
|---|
| 520 | This has been dropped as default
|
|---|
| 521 | long ago because it may not always be the
|
|---|
| 522 | address of the client machine.
|
|---|
| 523 | To enable this method, use
|
|---|
| 524 | </p>
|
|---|
| 525 | <p>
|
|---|
| 526 | <tt>SetClientFromAccept=</tt><i>true</i>
|
|---|
| 527 | </p>
|
|---|
| 528 | <p>
|
|---|
| 529 | in the <i>Misc</i> section of the server configuration
|
|---|
| 530 | file. If the address cannot be resolved, or reverse lookup of the
|
|---|
| 531 | resolved name fails, <i>no</i> error message will be issued,
|
|---|
| 532 | but the numerical address will be used.
|
|---|
| 533 | </p>
|
|---|
| 534 | </li>
|
|---|
| 535 | </ul><br><br></dd>
|
|---|
| 536 | <dt><b><a name="Client/Server4">4.5. Cannot resolve socket peer IP for client host=XXX peer=YYY</a></b></dt>
|
|---|
| 537 | <dd>See above<br><br></dd>
|
|---|
| 538 | <dt><b><a name="Client/Server5">4.6. Reverse lookup of socket peer failed host=XXX peer=YYY obj=ZZZ</a></b></dt>
|
|---|
| 539 | <dd>See above<br><br></dd>
|
|---|
| 540 | <dt><b><a name="Client/Server6">4.7. No socket peer alias matches client name host=XXX peer=YYY</a></b></dt>
|
|---|
| 541 | <dd>See above<br><br></dd>
|
|---|
| 542 | <dt><b><a name="Client/Server7">4.8. Session key negotiation failed</a></b></dt>
|
|---|
| 543 | <dd>See the document <a href="HOWTO-client+server-troubleshooting.html">HOWTO client+server troubleshooting</a><br><br></dd>
|
|---|
| 544 | <dt><b><a name="Client/Server8">4.9. Invalid connection attempt: Not in client list</a></b></dt>
|
|---|
| 545 | <dd>See the document <a href="HOWTO-client+server-troubleshooting.html">HOWTO client+server troubleshooting</a><br><br></dd>
|
|---|
| 546 | <dt><b><a name="Client/Server9">4.10. Invalid connection attempt: Session key mismatch</a></b></dt>
|
|---|
| 547 | <dd>See the document <a href="HOWTO-client+server-troubleshooting.html">HOWTO client+server troubleshooting</a><br><br></dd>
|
|---|
| 548 | <dt><b><a name="Client/Server10">4.11. How do I update the file signature database ?</a></b></dt>
|
|---|
| 549 | <dd>If you keep the file signature database on the server,
|
|---|
| 550 | the database is supposed to be updated on the server, using the
|
|---|
| 551 | <a href="http://www.la-samhna.de/beltane/">beltane</a>
|
|---|
| 552 | web-based console (currently in beta) and the
|
|---|
| 553 | log messages from the client.
|
|---|
| 554 | <p>
|
|---|
| 555 | Alternatively, you can <code>scp</code> the database
|
|---|
| 556 | to the client, run <code>samhain -t update -l none</code> (you
|
|---|
| 557 | need to avoid logging because otherwise you will get in conflict with
|
|---|
| 558 | the running samhain daemon), and then <code>scp</code> the
|
|---|
| 559 | database back to the server. Actually, with a properly set up
|
|---|
| 560 | "ssh", using RSA/DSA authentication
|
|---|
| 561 | and ssh-agent you could write a script to automate this.<br><br></dd>
|
|---|
| 562 | <dt><b><a name="Client/Server11">4.12. Time limit exceeded</a></b></dt>
|
|---|
| 563 | <dd>The respective client for that this message is generated has not
|
|---|
| 564 | sent anything for some interval of time (default 84600 sec = 1 day).
|
|---|
| 565 | The interval can be set as follows:
|
|---|
| 566 | <div class="block"><pre>
|
|---|
| 567 | [Misc]
|
|---|
| 568 | # unit is seconds
|
|---|
| 569 | SetClientTimeLimit=NNN
|
|---|
| 570 | </pre></div>
|
|---|
| 571 |
|
|---|
| 572 | This feature has the purpose to detect if a client is dead. You
|
|---|
| 573 | might want to ensure that timestamps are sent to the server:
|
|---|
| 574 | <div class="block"><pre>
|
|---|
| 575 | [Log]
|
|---|
| 576 | ExportSeverity=mark
|
|---|
| 577 | </pre></div>
|
|---|
| 578 | If you don't want to use this feature, set the time limit to some
|
|---|
| 579 | very large value.<br><br></dd>
|
|---|
| 580 | <dt><b><a name="Client/Server12">4.13. Invalid connection attempt: Signature mismatch</a></b></dt>
|
|---|
| 581 | <dd>Clients sign their messages using a session key negotiated
|
|---|
| 582 | with the server. The message indicates that the server could
|
|---|
| 583 | not verify the signature. This may be caused by a running two
|
|---|
| 584 | instances of samhain on the same client machine, both of them
|
|---|
| 585 | accessing the server (and negotiating different session keys
|
|---|
| 586 | ...). The system will recover automatically from the problem
|
|---|
| 587 | by forcing the failed client to negotiate a fresh session key.<br><br></dd>
|
|---|
| 588 | <dt><b><a name="Client/Server13">4.14. [Server] PANIC .. Address already in use subroutine=bind</a></b></dt>
|
|---|
| 589 | <dd>The server cannot bind to its port because the port is already used.
|
|---|
| 590 | Maybe you have accidentially already an instance of the
|
|---|
| 591 | server running.<br><br></dd>
|
|---|
| 592 | </dl>
|
|---|
| 593 | <hr><h2>5. Email</h2>
|
|---|
| 594 | <dl>
|
|---|
| 595 | <dt><b><a name="Email0">5.1. Reverse lookup failed</a></b></dt>
|
|---|
| 596 | <dd>Fix your DNS (reverse lookup: numerical IP address to FQDN, to verify
|
|---|
| 597 | FQDN to numerical IP address).
|
|---|
| 598 | <div class="block"><pre>
|
|---|
| 599 | Whether "nslookup" works is not very informative, because
|
|---|
| 600 | "nslookup" does not use the resolver library of the operating
|
|---|
| 601 | system. Therefore,
|
|---|
| 602 | it is not exactly the
|
|---|
| 603 | best tool for debugging name resolving problems (see the book
|
|---|
| 604 | "DNS and bind").
|
|---|
| 605 | </pre></div><br><br></dd>
|
|---|
| 606 | <dt><b><a name="Email1">5.2. From daemon@example.com</a></b></dt>
|
|---|
| 607 | <dd>samhain fails to resolve the
|
|---|
| 608 | self-address of the host.
|
|---|
| 609 | See 'Client cannot self-resolve' in the 'Most frequently' section.<br><br></dd>
|
|---|
| 610 | <dt><b><a name="Email2">5.3. How do I define more than one email addresses ?</a></b></dt>
|
|---|
| 611 | <dd>Use <tt>SetMailAddress=...</tt> multiple times (upt to eight addresses
|
|---|
| 612 | are possible, with at most 63 characters per address):
|
|---|
| 613 | <div class="block"><pre>
|
|---|
| 614 | [Misc]
|
|---|
| 615 | SetMailAddress=aaa@foo.com
|
|---|
| 616 | SetMailAddress=bbb@foo.com
|
|---|
| 617 | </pre></div><br><br></dd>
|
|---|
| 618 | </dl>
|
|---|
| 619 | <hr><h2>6. Misc</h2>
|
|---|
| 620 | <dl>
|
|---|
| 621 | <dt><b><a name="Misc0">6.1. Error message: "Invalid line XYZ in configuration file"</a></b></dt>
|
|---|
| 622 | <dd>This message indicates that line XYZ in the configuration file contains
|
|---|
| 623 | an unrecognized directive. The primary reasons are:<br />
|
|---|
| 624 |
|
|---|
| 625 | (a) The directive should be placed into a particular section of the
|
|---|
| 626 | configuration file, but the section header is not present (or you forgot
|
|---|
| 627 | to uncomment it).<br />
|
|---|
| 628 |
|
|---|
| 629 | (b) Samhain is compiled without support for this directive.<br />
|
|---|
| 630 |
|
|---|
| 631 | (c) You have a typo in the directive.<br /><br><br></dd>
|
|---|
| 632 | <dt><b><a name="Misc1">6.2. Why do I get a local logfile if I log to the server ?</a></b></dt>
|
|---|
| 633 | <dd>Because you can use all log facilities in parallel. You should
|
|---|
| 634 | switch off in the config file what you don't want/need:
|
|---|
| 635 | <div class="block"><pre>
|
|---|
| 636 | [Log]
|
|---|
| 637 | # local log file
|
|---|
| 638 | LogSeverity=none
|
|---|
| 639 | </pre></div><br><br></dd>
|
|---|
| 640 | <dt><b><a name="Misc2">6.3. Why is there no NIS support with a static samhain executable on Linux ?</a></b></dt>
|
|---|
| 641 | <dd>Some functions (including NIS) require
|
|---|
| 642 | libraries that are only available as shared libraries
|
|---|
| 643 | with modern GLIBC versions. While you can always compile a static
|
|---|
| 644 | executable, normally it would still open the shared library at runtime.
|
|---|
| 645 | As of version 1.8.11, samhain avoids this by providing replacement
|
|---|
| 646 | functions from uClibc. However, these do not include NIS support.<br><br></dd>
|
|---|
| 647 | <dt><b><a name="Misc3">6.4. Why do I get hundreds of messages about modified CTIME ?</a></b></dt>
|
|---|
| 648 | <dd>This happens because some
|
|---|
| 649 | backup applications reset the atime/mtime timestamps, which causes
|
|---|
| 650 | the ctime timestamp to be modified (rootkits avoid this by
|
|---|
| 651 | temporarily resetting the system clock to the original ctime ...).
|
|---|
| 652 | <p>
|
|---|
| 653 | To fix this problem, read the manual of your backup application, or
|
|---|
| 654 | redefine the ReadOnly policy to <i>not</i> check
|
|---|
| 655 | the ctime timestamp:
|
|---|
| 656 | <div class="block"><pre>
|
|---|
| 657 | [Misc]
|
|---|
| 658 | RedefReadOnly=-CTM
|
|---|
| 659 | </pre></div>
|
|---|
| 660 | <div class="warnblock"><pre>
|
|---|
| 661 | Order matters - you must <i>first</i> redefine
|
|---|
| 662 | ReadOnly <i>before</i> you use it
|
|---|
| 663 | </pre></div><br><br></dd>
|
|---|
| 664 | <dt><b><a name="Misc4">6.5. PANIC — File not accessible</a></b></dt>
|
|---|
| 665 | <dd>Most likely permission denied because of unsufficient privileges.<br><br></dd>
|
|---|
| 666 | <dt><b><a name="Misc5">6.6. How can I avoid error messages for invalid UIDs (no such user) ?</a></b></dt>
|
|---|
| 667 | <dd>Set SeverityNames to a low value
|
|---|
| 668 | <div class="block"><pre>
|
|---|
| 669 | [EventSeverity]
|
|---|
| 670 | SeverityNames=debug
|
|---|
| 671 | </pre></div><br><br></dd>
|
|---|
| 672 | <dt><b><a name="Misc6">6.7. [Redhat] The /etc/init.d/(samhain|yule) init script hangs</a></b></dt>
|
|---|
| 673 | <dd>Redhat uses "initlog" (see
|
|---|
| 674 | <code>man initlog</code>) in initscripts. If it hangs, most probably
|
|---|
| 675 | samhain/yule runs in the foreground rather than as daemon. Set
|
|---|
| 676 | daemon mode in the configuration file:
|
|---|
| 677 | <div class="block"><pre>
|
|---|
| 678 | [Misc]
|
|---|
| 679 | Daemon=yes
|
|---|
| 680 | </pre></div><br><br></dd>
|
|---|
| 681 | <dt><b><a name="Misc7">6.8. The /etc/init.d/(samhain|yule) init script exits with: execvp: No such file or directory</a></b></dt>
|
|---|
| 682 | <dd>Either the program is not installed, or it is not in the PATH (the one
|
|---|
| 683 | used by the init script, which may be different from your PATH).<br><br></dd>
|
|---|
| 684 | <dt><b><a name="Misc8">6.9. Why am I not receiving the "BEGIN LOGKEY" message by email ?</a></b></dt>
|
|---|
| 685 | <dd>This message (which contains the key to verify the log file) is generated
|
|---|
| 686 | when logging to the log file starts. It has the severity "ALRT",
|
|---|
| 687 | thus you should make sure that you have set the logging threshold for
|
|---|
| 688 | email correctly to receive it.<br><br></dd>
|
|---|
| 689 | <dt><b><a name="Misc9">6.10. Why does console logging fail if I compile with
|
|---|
| 690 | <code>--enable-(micro-)stealth</code> ?</a></b></dt>
|
|---|
| 691 | <dd>The default logging options are more "stealthy". Set the
|
|---|
| 692 | threshold explicitely rather than relying on the default.<br><br></dd>
|
|---|
| 693 | <dt><b><a name="Misc10">6.11. I need a list for my schedule !</a></b></dt>
|
|---|
| 694 | <dd>You can have the same effect with a list of schedules. See the section
|
|---|
| 695 | "Timing file checks" in the manual.<br><br></dd>
|
|---|
| 696 | <dt><b><a name="Misc11">6.12. The hiding kernel module has no effect !</a></b></dt>
|
|---|
| 697 | <dd>Most probably you compiled using the wrong "System.map" file.<br><br></dd>
|
|---|
| 698 | <dt><b><a name="Misc12">6.13. What does the message "Large lstat/open overhead" mean ?</a></b></dt>
|
|---|
| 699 | <dd>Your system needs several seconds to proceed from an lstat() system call
|
|---|
| 700 | to an open() system call. This is a tremenduous overhead, and
|
|---|
| 701 | indicates that either your system has a really severe performance problem,
|
|---|
| 702 | or someone tries to slow down samhain.<br><br></dd>
|
|---|
| 703 | <dt><b><a name="Misc13">6.14. What does the message "Device not available path=/dev/random" mean ? I have /dev/random !</a></b></dt>
|
|---|
| 704 | <dd>/dev/random blocks unless there is some entropy it can deliver. Samhain
|
|---|
| 705 | will time out and fall back on /dev/urandom after some seconds to avoid
|
|---|
| 706 | hanging for a potentially long time. It will try /dev/random again next
|
|---|
| 707 | time it needs entropy.<br><br></dd>
|
|---|
| 708 | <dt><b><a name="Misc14">6.15. Logging to an external program fails; the program receives no data
|
|---|
| 709 | on stdin !</a></b></dt>
|
|---|
| 710 | <dd>Probably your program is not designed to <i>wait for input</i>, but exits
|
|---|
| 711 | if reading fails (because there is no data <i>yet</i>). You may want to
|
|---|
| 712 | let your program wait for the terminating "[EOF]" line.<br><br></dd>
|
|---|
| 713 | <dt><b><a name="Misc15">6.16. SIGILL on AIX</a></b></dt>
|
|---|
| 714 | <dd>For each scanned file, samhain needs to
|
|---|
| 715 | store some information in memory (e.g. to recognize changes that have
|
|---|
| 716 | already been reported, and avoid duplicate reports). On AIX, if you are
|
|---|
| 717 | checking a <i>really huge</i> number of files,
|
|---|
| 718 | memory usage may exceed the default limit of 256 MB, and the process may
|
|---|
| 719 | terminate with SIGILL.
|
|---|
| 720 | <p>
|
|---|
| 721 | The problem can be solved by linking with the flag
|
|---|
| 722 | <code>-bmaxdata:0x80000000</code>. This allows the application to
|
|---|
| 723 | access up to 8 segments (where each segment is 256MB).
|
|---|
| 724 | <p>
|
|---|
| 725 | If you are using gcc, you need to use instead
|
|---|
| 726 | the flag <code>-Wl,bmaxdata:0x80000000</code>, which tells
|
|---|
| 727 | gcc to pass on the
|
|---|
| 728 | <i>bmaxdata</i>
|
|---|
| 729 | flag to the AIX linker. You can use the LDFLAGS environment variable to
|
|---|
| 730 | pass linker flags to the configure script:
|
|---|
| 731 | <div class="block"><pre>
|
|---|
| 732 | export LDFLAGS="-Wl,bmaxdata:0x80000000"
|
|---|
| 733 | </pre></div><br><br></dd>
|
|---|
| 734 | </dl>
|
|---|
| 735 | <hr><h2>7. Database</h2>
|
|---|
| 736 | <dl>
|
|---|
| 737 | <dt><b><a name="Database0">7.1. Why are client messages corrupted / incompletely stored in the DB ?</a></b></dt>
|
|---|
| 738 | <dd>Because the messages are not in XML format, and therefore incorrectly
|
|---|
| 739 | parsed. The most frequent reasons are:
|
|---|
| 740 | <div class="block"><pre>
|
|---|
| 741 | 1.) Your server is compiled with --enable-xml-log, but your client(s)
|
|---|
| 742 | is/are not.
|
|---|
| 743 |
|
|---|
| 744 | 2.) In your client or server configuration file, you are using
|
|---|
| 745 | the option for a custum message header, but without paying attention
|
|---|
| 746 | to preserving the XML format.
|
|---|
| 747 | </pre></div><br><br></dd>
|
|---|
| 748 | <dt><b><a name="Database1">7.2. I want / don't want the server timestamps (for client messages) in the SQL database</a></b></dt>
|
|---|
| 749 | <dd><div class="block"><pre>
|
|---|
| 750 | [Database]
|
|---|
| 751 | SetDBServerTstamp = true/false
|
|---|
| 752 | </pre></div>
|
|---|
| 753 |
|
|---|
| 754 | This will enable/disable logging of the server timestamp for client
|
|---|
| 755 | messages. The server timestamp will be written to a seperate record,
|
|---|
| 756 | with <i>log_ref</i> set to the value of
|
|---|
| 757 | <i>log_index</i> of the corresponding client message.<br><br></dd>
|
|---|
| 758 | <dt><b><a name="Database2">7.3. I don't want the client TIMESTAMP messages in the SQL database</a></b></dt>
|
|---|
| 759 | <dd><div class="block"><pre>
|
|---|
| 760 | Sending timestamps from the client allows the server to detect if
|
|---|
| 761 | a client is not running anymore (use SetClientTimeLimit=NNN in the
|
|---|
| 762 | [Misc] section of the server config file to set the number of seconds
|
|---|
| 763 | after which the server will issue an error message if no timestamp has
|
|---|
| 764 | been received).
|
|---|
| 765 | </pre></div>
|
|---|
| 766 |
|
|---|
| 767 | However, you might not want to log these timestamps to the database
|
|---|
| 768 | (or other log facilities). To filter them, you can use two methods
|
|---|
| 769 | (examples are for the SQL database).
|
|---|
| 770 | The first
|
|---|
| 771 | one has the disadvantage that only messages of
|
|---|
| 772 | severity <i>err</i> or higher will be logged:
|
|---|
| 773 | <div class="block"><pre>
|
|---|
| 774 | [Misc]
|
|---|
| 775 | UseClientSeverity=yes
|
|---|
| 776 |
|
|---|
| 777 | [Log]
|
|---|
| 778 | DatabaseSeverity=err
|
|---|
| 779 | </pre></div>
|
|---|
| 780 |
|
|---|
| 781 | The second method is more specific — log everything not
|
|---|
| 782 | belonging to the STAMP class of messages:
|
|---|
| 783 | <div class="block"><pre>
|
|---|
| 784 | [Misc]
|
|---|
| 785 | UseClientClass=yes
|
|---|
| 786 |
|
|---|
| 787 | [Log]
|
|---|
| 788 | DatabaseClass=PANIC RUN FIL TCP ERR ENET EINPUT
|
|---|
| 789 | </pre></div><br><br></dd>
|
|---|
| 790 | <dt><b><a name="Database3">7.4. What does the log_ref field mean ?</a></b></dt>
|
|---|
| 791 | <dd>NULL are client messages. Nonzero integer is a server timestamp
|
|---|
| 792 | for a client message (where log_ref indicates the log_index entry
|
|---|
| 793 | number of the corresponding client message). Zero indicates a message
|
|---|
| 794 | by the server itself (e.g. the server's start message).<br><br></dd>
|
|---|
| 795 | </dl>
|
|---|
| 796 | <hr>
|
|---|
| 797 |
|
|---|
| 798 | <p>Copyright (c) 2004 Rainer Wichmann</p>
|
|---|
| 799 |
|
|---|
| 800 | <p><i>This list of questions and answers was generated by
|
|---|
| 801 | <a href="http://www.makefaq.org/">makefaq</a>.</i>
|
|---|
| 802 |
|
|---|
| 803 | </div>
|
|---|
| 804 | </body>
|
|---|
| 805 | </html>
|
|---|
