Detect F5 TMUI RCE CVE-2020-5902


Description

The following analytic identifies remote code execution (RCE) attempts targeting F5 BIG-IP, BIG-IQ, and Traffix SDC devices, specifically exploiting CVE-2020-5902. It uses regex to detect patterns in syslog data that match known exploit strings such as "hsqldb;" and directory traversal sequences. This activity is significant because successful exploitation can allow attackers to execute arbitrary commands on the affected devices, leading to full system compromise. If confirmed malicious, this could result in unauthorized access, data exfiltration, or further lateral movement within the network.

Query · spl

`f5_bigip_rogue` | regex _raw="(hsqldb;|.*\\.\\.;.*)" | search `detect_f5_tmui_rce_cve_2020_5902_filter`

Implementation guide

To consistently detect exploit attempts on F5 devices using the vulnerabilities contained within CVE-2020-5902 it is recommended to ingest logs via syslog. As many BIG-IP devices will have SSL enabled on their management interfaces, detections via wire data may not pick anything up unless you are decrypting SSL traffic in order to inspect it. I am using a regex string from a Cloudflare mitigation technique to try and always catch the offending string (..;), along with the other exploit of using (hsqldb;).

Known false positives

  • No false positives have been identified at this time.

Analyst notes

Known false positives: No false positives have been identified at this time.

Raw source Detect F5 TMUI RCE CVE-2020-5902 · SPL
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Published by splunk/security_content ↗, licensed under Apache 2.0 ↗. Reproduced here unmodified.
name: Detect F5 TMUI RCE CVE-2020-5902
id: 810e4dbc-d46e-11ea-87d0-0242ac130003
version: 10
creation_date: '2020-08-04'
modification_date: '2026-08-10'
author: Shannon Davis, Splunk
status: deprecated
type: TTP
description: The following analytic identifies remote code execution (RCE) attempts targeting F5 BIG-IP, BIG-IQ, and Traffix SDC devices, specifically exploiting CVE-2020-5902. It uses regex to detect patterns in syslog data that match known exploit strings such as "hsqldb;" and directory traversal sequences. This activity is significant because successful exploitation can allow attackers to execute arbitrary commands on the affected devices, leading to full system compromise. If confirmed malicious, this could result in unauthorized access, data exfiltration, or further lateral movement within the network.
data_source: []
search: '`f5_bigip_rogue` | regex _raw="(hsqldb;|.*\\.\\.;.*)" | search `detect_f5_tmui_rce_cve_2020_5902_filter`'
how_to_implement: To consistently detect exploit attempts on F5 devices using the vulnerabilities contained within CVE-2020-5902 it is recommended to ingest logs via syslog.  As many BIG-IP devices will have SSL enabled on their management interfaces, detections via wire data may not pick anything up unless you are decrypting SSL traffic in order to inspect it.  I am using a regex string from a Cloudflare mitigation technique to try and always catch the offending string (..;), along with the other exploit of using (hsqldb;).
known_false_positives: No false positives have been identified at this time.
references:
    - https://www.ptsecurity.com/ww-en/about/news/f5-fixes-critical-vulnerability-discovered-by-positive-technologies-in-big-ip-application-delivery-controller/
    - https://support.f5.com/csp/article/K52145254
finding:
    title: Potential F5 TMUI RCE traffic [ $dest$ ]
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - F5 TMUI RCE CVE-2020-5902
asset_type: Network
cve:
    - CVE-2020-5902
mitre_attack_id:
    - T1190
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: web
security_domain: network
deprecation_info:
    reason: Detection deprecated as it is targeting a 6 years old CVE that is no longer relevant, since the OS version targeted is no longer supported by F5. As well, the fact that the detection has been set to experimental since 2020.
    removed_in_version: 6.6.0
    replacement_content: []

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