Apache stores details of HTTP requests in its Access Log as defined by the CustomLog directive. The log can be used to check for malicious requests such as hacking or defacement attempts.

Scalp! is a security log analyzer for Apache. It automates reading the Apache log files and perform threat analysis.

Scalp! uses rulesets provided by PHP-IDS project and is available for download from GitHub.

Steps to perform threat analysis on Apache log using Scalp:

  1. Download Scalp from GitHub.
    $ git clone https://github.com/neuroo/apache-scalp scalp
    Cloning into 'scalp'...
    remote: Enumerating objects: 11, done.
    remote: Total 11 (delta 0), reused 0 (delta 0), pack-reused 11
    Unpacking objects: 100% (11/11), 11.85 KiB | 346.00 KiB/s, done.
  2. Download signature file from PHPIDS project on GitHub.
    $ git clone https://github.com/PHPIDS/PHPIDS phpids
    Cloning into 'phpids'...
    remote: Enumerating objects: 11281, done.
    remote: Total 11281 (delta 0), reused 0 (delta 0), pack-reused 11281
    Receiving objects: 100% (11281/11281), 4.16 MiB | 2.81 MiB/s, done.
    Resolving deltas: 100% (5636/5636), done.
  3. Split Apache log file if longer than 10000 lines.
    $ split -l 10000  /var/log/apache2/access_log
  4. Analyze Apache log file using Scalp and PHPIDS signature.
    $ sudo python scalp/scalp.py --log /var/log/apache2/access_log --filters phpids/lib/IDS/default_filter.xml
    Password:
    Loading XML file 'phpids/lib/IDS/default_filter.xml'...
    Processing the file '/var/log/apache2/access_log'...
    Scalp results:
    	Processed 1318 lines over 1318
    	Found 6 attack patterns in 0.425544 s
    Generating output in /home/user/access_log_scalp_*

    More options for Scalp:

    Scalp the apache log! by Romain Gaucher - http://rgaucher.info
    usage:  ./scalp.py [--log|-l log_file] [--filters|-f filter_file] [--period time-frame] [OPTIONS] [--attack a1,a2,..,an]
                       [--sample|-s 4.2]
       --log       |-l:  the apache log file './access_log' by default
       --filters   |-f:  the filter file     './default_filter.xml' by default
       --exhaustive|-e:  will report all type of attacks detected and not stop
                         at the first found
       --tough     |-u:  try to decode the potential attack vectors (may increase
                         the examination time)
       --period    |-p:  the period must be specified in the same format as in
                         the Apache logs using * as wild-card
                         ex: 04/Apr/2008:15:45;*/Mai/2008
                         if not specified at the end, the max or min are taken
       --html      |-h:  generate an HTML output
       --xml       |-x:  generate an XML output
       --text      |-t:  generate a simple text output (default)
       --except    |-c:  generate a file that contains the non examined logs due to the
                         main regular expression; ill-formed Apache log etc.
       --attack    |-a:  specify the list of attacks to look for
                         list: xss, sqli, csrf, dos, dt, spam, id, ref, lfi
                         the list of attacks should not contains spaces and comma separated
                         ex: xss,sqli,lfi,ref
       --ignore-ip|-i:  specify the list of IP Addresses to look exclude
                         the list of IP Addresses should be comma separated and not contain spaces
                         This option can be used in conjunction with --ignore-ip
       --ignore-subnet|-n:  specify the list of Subnets to look exclude
                         the list of Subnets should be comma separated and not contain spaces
                         This option can be used in conjunction with --ignore-subnet
       --output    |-o:  specifying the output directory; by default, scalp will try to write
                         in the same directory as the log file
       --sample    |-s:  use a random sample of the lines, the number (float in [0,100]) is
                         the percentage, ex: --sample 0.1 for 1/1000
  5. Review generated output.
    $ cat /home/user/access_log_scalp_*
    
    #
    # File created by Scalp! by Romain Gaucher - http://code.google.com/p/apache-scalp
    # Apache log attack analysis tool based on PHP-IDS filters
    #
    Scalped file: access_log
    Creation date: Sat-08-Feb-2020
    
    Attack type: files
    Attack Cross-Site Scripting (xss)
    Attack Cross-Site Request Forgery (csrf)
    Attack Spam (spam)
    Attack Local File Inclusion (lfi)
    
    	### Impact 5
    	127.0.0.1 - - [08/Feb/2020:07:31:12 +0800] "GET /windows/start HTTP/1.1" 200 4541
    	Reason: "Detects specific directory and path traversal"
    
    	127.0.0.1 - - [08/Feb/2020:07:31:16 +0800] "GET /windows/burn-iso-image HTTP/1.1" 200 4941
    	Reason: "Detects specific directory and path traversal"
    
    	127.0.0.1 - - [08/Feb/2020:07:31:17 +0800] "GET /_media/windows/burn-iso-image/windows7-burn-iso-explorer-write-to-disc.png?w=400&tok=e21342 HTTP/1.1" 200 16104
    	Reason: "Detects specific directory and path traversal"
    
    	127.0.0.1 - - [08/Feb/2020:07:31:17 +0800] "GET /windows/disable-system-restore HTTP/1.1" 200 4679
    	Reason: "Detects specific directory and path traversal"
    
    	127.0.0.1 - - [08/Feb/2020:07:31:18 +0800] "GET /windows/firewall-command HTTP/1.1" 200 5511
    	Reason: "Detects specific directory and path traversal"
    
    	127.0.0.1 - - [08/Feb/2020:07:31:19 +0800] "GET /windows/restore-mbr HTTP/1.1" 200 5323
    	Reason: "Detects specific directory and path traversal"
    
    Attack SQL Injection (sqli)
    Attack type: format string
    Attack Remote File Execution (rfe)
    Attack Denial Of Service (dos)
    Attack Directory Traversal (dt)
    Attack Information Disclosure (id)
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