Citrix Netscaler Attack CVE-2019-19781

calendar Jun 20, 2023 · attack.initial_access attack.t1190 cve.2019.19781 detection.emerging_threats  ·
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Detects CVE-2019-19781 exploitation attempt against Citrix Netscaler, Application Delivery Controller and Citrix Gateway Attack

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 1title: Citrix Netscaler Attack CVE-2019-19781
 2id: ac5a6409-8c89-44c2-8d64-668c29a2d756
 3status: test
 4description: Detects CVE-2019-19781 exploitation attempt against Citrix Netscaler, Application Delivery Controller and Citrix Gateway Attack
 5references:
 6    - https://support.citrix.com/article/CTX267679
 7    - https://support.citrix.com/article/CTX267027
 8    - https://isc.sans.edu/diary/25686
 9    - https://twitter.com/mpgn_x64/status/1216787131210829826
10    - https://github.com/x1sec/CVE-2019-19781/blob/25f7ab97275b2d41800bb3414dac8ca3a78af7e5/CVE-2019-19781-DFIR.md
11author: Arnim Rupp, Florian Roth
12date: 2020/01/02
13modified: 2023/01/02
14tags:
15    - attack.initial_access
16    - attack.t1190
17    - cve.2019.19781
18    - detection.emerging_threats
19logsource:
20    category: webserver
21    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.'
22detection:
23    selection_cs:
24        - cs-uri-query|contains: '/../vpns/'
25        - cs-uri-query|endswith: '/vpns/cfg/smb.conf'
26    selection_csall:
27        cs-uri-query|contains|all:
28            - '/vpns/portal/scripts/'
29            - '.pl'
30    condition: 1 of selection_*
31fields:
32    - client_ip
33    - vhost
34    - url
35    - response
36falsepositives:
37    - Unknown
38level: critical

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