Overview

HTTPS SSH
    malmon - MALware MONitor

About:

malmon is a small peace of software witch is very useful for web hosting server (and not only). It uses inotify (pyinotify) to monitor file system activity and checks every new / movied / modified file (there's a file size limit , so we can check only files smaller then X size). Currently there two type of checks:

# md5 sum check.
    * We have a db of md5 sums of some known
      malware/exploits/backdoors and stuff like that
      and we compare them to the md5 sum of the new/
      modified file.
# hex signature check.
    * We check the file content and match it
      agains another db with known hex signatures.

Features:

1). Realtime file system multi threaded monitoring
2). md5 sum checks
3). hex signature based checks
4). exclude file (supports reg expr)
5). Auto update [md5sums & hex sigs]
6). Check only files smaller them some
size (size limit is set in the config)
7). Shitlist added. A list of forbiden filenames
This will move all files with name found in
the shitlist, without doing any checks
8). Add warn/paranoid mode option
    In paranoid mode (default) we mode all
    infections to the quarantine dir
    In warn mode, we will only print them
    in the log/stdout, without moving them
9). Lower process priorit (lower resurse usage)
10). Add/Remove directories in watch list while
    running (throu the UNIX socket)
11). Force update (throu the UNIX socket)
12). New option - scan directories for malware

What's to come:

1). Add MIME Type check.
2). Add spam-filter like checks.
    We will analyze the file, and match
    any strings that are often found in
    malware/backdoors/exploits.
    Every sting will have factor, and
    after the analyze is done, we check
    what factor has the file get, and if
    its bigger then allowed we'll add
    warning to the log/stdout (depending
    in what mode is the daemon running)
3). Mail reports (daily and on event)

Layout:

/usr/local/sbin/malmon       - The daemon
/usr/local/sbin/malmon-scan  - Scanning tool
/etc/malmon                  - Configuration dir
/etc/malmon/malmon.conf      - Config file
/etc/malmon/black.list       - Backlist file (supports reg expr)
/etc/malmon/exclude.list     - Exclude list (supports reg expr)
/var/cache/malmon            - The daemon cache directory
/var/cache/malmon/infected   - Where to move all infected files
/var/run/malmon.pid          - The pidfile
/var/run/malmon.sock         - Unix socket file

Known issues

If you get WD=-1 No space left on device (ENOSPC) this means you've reached the kernel fs.inotify.max_user_watches limit

sysctl -n fs.inotify.max_user_watches       # to read it
sysctl -n -w fs.inotify.max_user_watches=16384  # to modify it

Deps:

# inotify kernel support    (CONFIG_INOTIFY_USER=y)
# pyinotify module      (http://pyinotify.sourceforge.net/)

If you have them both, you're good to go :]

Small tip:

hashlib became part of Python in version 2.6
    if you're using older version, you'll need to
    get hashlib for python2.4+ from python.org.
malmon was only tested with Python2.5...so
    no clue if it will work with 2.4 (it should!)