Exploit Framework User Agent

title: Exploit Framework User Agent
id: fdd1bfb5-f60b-4a35-910e-f36ed3d0b32f
status: test
description: Detects suspicious user agent strings used by exploit / pentest frameworks like Metasploit in proxy logs
references:
    - https://blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/
author: Florian Roth (Nextron Systems)
date: 2017-07-08
modified: 2025-01-18
tags:
    - attack.command-and-control
    - attack.t1071.001
logsource:
    category: proxy
detection:
    selection:
        c-useragent:
        # Cobalt Strike https://www.cobaltstrike.com/help-malleable-c2
            - 'Internet Explorer *'
            - 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; InfoPath.2)' # https://bluescreenofjeff.com/2016-06-28-cobalt-strike-http-c2-redirectors-with-apache-mod_rewrite/

        # Metasploit Framework - Analysis by Didier Stevens https://blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/
            - 'Mozilla/4.0 (compatible; Metasploit RSPEC)'
            - 'Mozilla/4.0 (compatible; MSIE 6.1; Windows NT)'
            - 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)' # old browser, rare, base-lining needed
            - 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)' # old browser, rare, base-lining needed
            - 'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0)' # old browser, rare, base-lining needed
            - 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Trident/4.0; SIMBAR={7DB0F6DE-8DE7-4841-9084-28FA914B0F2E}; SLCC1; .N'
            - 'Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)' # only use in proxy logs - not for detection in web server logs
            - 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.13 (KHTML, like Gecko) Chrome/4.0.221.6 Safari/525.13'
            - 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; MAAU)' # Payloads

        # Metasploit Update by Florian Roth 08.07.2017
            - 'Mozilla/5.0'
            - 'Mozilla/4.0 (compatible; SPIPE/1.0'
        # - 'Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0)'  # too many false positives expected
        # - 'Mozilla/5.0 (Windows NT 6.1; Trident/7.0; rv:11.0) like Gecko'  # too many false positives expected
            - 'Mozilla/5.0 (Windows NT 6.3; rv:39.0) Gecko/20100101 Firefox/35.0'
            - 'Sametime Community Agent' # Unknown if prone to false positives - https://github.com/rapid7/metasploit-framework/blob/97095ab3113de2f046e64a64c461a1f888554401/modules/exploits/windows/http/steamcast_useragent.rb
            - 'X-FORWARDED-FOR'
            - 'DotDotPwn v2.1'
            - 'SIPDROID'
            - 'Mozilla/5.0 (Windows NT 10.0; Win32; x32; rv:60.0)' # CobaltStrike https://unit42.paloaltonetworks.com/tracking-oceanlotus-new-downloader-kerrdown/

        # Empire
            - 'Mozilla/6.0 (X11; Linux x86_64; rv:24.0) Gecko/20140205     Firefox/27.0 Iceweasel/25.3.0'

        # Exploits
            - '*wordpress hash grabber*'
            - '*exploit*'

        # Havoc
            - 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.110 Safari/537.36'  # https://github.com/HavocFramework/Havoc/issues/519
    condition: selection
falsepositives:
    - Unknown
level: high