title: Citrix Netscaler Attack CVE-2019-19781
id: ac5a6409-8c89-44c2-8d64-668c29a2d756
status: test
description: Detects CVE-2019-19781 exploitation attempt against Citrix Netscaler, Application Delivery Controller and Citrix Gateway Attack
author: Arnim Rupp, Florian Roth
references:
  - https://support.citrix.com/article/CTX267679
  - https://support.citrix.com/article/CTX267027
  - https://isc.sans.edu/diary/25686
  - https://twitter.com/mpgn_x64/status/1216787131210829826
  - https://github.com/x1sec/x1sec.github.io/blob/master/CVE-2019-19781-DFIR.md
date: 2020/01/02
modified: 2021/11/27
logsource:
  category: webserver
  definition: 'Make sure that your Netscaler appliance logs all kinds of attacks (test with http://your-citrix-gw.net/robots.txt). The directory traversal with ../ might not be needed on certain cloud instances or for authenticated users, so we also check for direct paths. All scripts in portal/scripts are exploitable except logout.pl.'
detection:
  selection:
    c-uri:
      - '*/../vpns/*'
      - '*/vpns/cfg/smb.conf'
      - '*/vpns/portal/scripts/*.pl*'
  condition: selection
fields:
  - client_ip
  - vhost
  - url
  - response
falsepositives:
  - Unknown
level: critical
tags:
  - attack.initial_access
  - attack.t1190
