/usr/share/doc/samhain/manual.html/file-content-store.html

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>5.20. Storing the full content of a file (aka: WHAT has changed?)</A
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>Consider using a revision control system</B
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>  One of the most frequently requested features is the ability to
  determine <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>what</I
></SPAN
> has changed in a file. This
  is not really within the scope of a 
  <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>file integrity checker</I
></SPAN
>;
  rather it would be the task of a <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>revision control system</I
></SPAN
>
  like <SPAN
CLASS="APPLICATION"
>SVN (subversion)</SPAN
> or 
  <SPAN
CLASS="APPLICATION"
>CVS</SPAN
>.
  </P
><P
>  While samhain, as of version 2.4.4, supports storing the full content
  of files in the baseline database, this feature is limited to 
  <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>small</I
></SPAN
>
  files (smaller than 9200 bytes after zlib compression). If you really think
  you need this feature, it is recommended to evaluate whether a
  <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>revision control system</I
></SPAN
> does not fit your needs better.
  </P
></TD
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><P
>As of version 2.4.4, samhain can optionally store the full literal
content of regular files in the database, which allows to determine
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>what</I
></SPAN
> has changed in a file.
This feature will only get compiled if the required zlib development 
environment is available on the host where <SPAN
CLASS="APPLICATION"
>samhain</SPAN
> 
is compiled (e.g. on Debian Linux, the package zlib1g-dev).
This feature is subject to the following restrictions:

<P
></P
><UL
><LI
><P
>        Only small files can be stored, where 'small' means less than 9200
	bytes after zlib compression (and less than 92000 bytes before 
	compression, i.e. files 10 times larger than the limit are assumed 
	to not compress below the limit).
  </P
></LI
><LI
><P
>        Only regular files can be stored; in particular, symlinks are not
	stored, since the <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>content</I
></SPAN
> of a symlink
	inode actually is the target path (which is stored literally).
	It is safe to enable this for a directory, in the sense that it is
	silently ignored for file types where it does not apply.
  </P
></LI
><LI
><P
>        The feature must be explicitely enabled in the runtime configuration
	file by adding the '+TXT' to the monitoring policy of a file 
	or directory.
  </P
></LI
></UL
></P
><P
>To enable this feature, modify a policy to include 'TXT', and place
the desired files under this policy (see example below).</P
><P
>In order to show the stored content of a file, use the following
command:
  <PRE
CLASS="SCREEN"
>  <SAMP
CLASS="PROMPT"
>sh$ </SAMP
><KBD
CLASS="USERINPUT"
>samhain --list-file <TT
CLASS="REPLACEABLE"
><I
>path</I
></TT
> -d <TT
CLASS="REPLACEABLE"
><I
>database_path</I
></TT
></KBD
>
  </PRE
></P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN3172"
>5.20.1. Example configuration</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>&#13;  [Misc]
  #
  # UserN policies default to ReadOnly + ATM (access time). This
  # makes the default (intentionally ;-) more or less useless.
  #
  # Redefine to ReadOnly + TXT (store file content)
  #
  RedefUser0 = -ATM, +TXT

  [User0]
  #
  # Files for which we want to store the full content in the
  # baseline database.
  #
  file=/etc/passwd
  file=/etc/group

  </PRE
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN3175"
>5.20.2. Implementation details</A
></H2
><P
>  File contents are zlib compressed (RFC 1950), and the compressed data
  are base64 encoded. To avoid internal conflicts, 
  <SPAN
CLASS="APPLICATION"
>samhain</SPAN
> uses the letters '(', ')' and '?'
  instead of the letters '+', '/', and '=' used in standard base64 encoding.
  E.g. in PHP the following will decode the data:
  </P
><PRE
CLASS="PROGRAMLISTING"
>  $tmp1 = strtr($data, "()?", "+/=");
  $tmp2 = base64_decode($tmp1);
  $tmp3 = gzuncompress($tmp2);
  </PRE
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samhain 3.1.0-5ubuntu1 / usr / share / doc / samhain / manual.html / file-content-store.html
