SigmaHQ/rules/web/win_webshell_regeorg.yml
2021-08-22 13:57:56 +02:00

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YAML

title: Webshell ReGeorg Detection Via Web Logs
id: 2ea44a60-cfda-11ea-87d0-0242ac130003
status: experimental
description: Certain strings in the uri_query field when combined with null referer and null user agent can indicate activity associated with the webshell ReGeorg.
author: Cian Heasley
date: 2020/08/04
modified: 2020/09/03
references:
- https://community.rsa.com/community/products/netwitness/blog/2019/02/19/web-shells-and-netwitness-part-3
- https://github.com/sensepost/reGeorg
logsource:
category: webserver
detection:
selection:
uri_query|contains:
- 'cmd=read'
- 'connect&target'
- 'cmd=connect'
- 'cmd=disconnect'
- 'cmd=forward'
filter:
referer: null
useragent: null
method: POST
condition: selection and filter
fields:
- uri_query
- referer
- method
- useragent
falsepositives:
- web applications that use the same URL parameters as ReGeorg
level: high
tags:
- attack.persistence
- attack.t1100 # an old one
- attack.t1505.003