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tcp: generic detection bypass using TCP urgent support

High
victorjulien published GHSA-69wr-vhwg-84h2 Jan 6, 2025

Package

suricata

Affected versions

< 7.0.8

Patched versions

7.0.8

Description

Impact

TCP streams with TCP urgent data (out of band data) can lead to Suricata analyzing data differently than the applications at the TCP endpoints, leading to possible evasions.

Patches

Suricata 7.0.8 includes options to allow users to configure how to handle TCP urgent data.

Workarounds

In IPS mode, you can use a rule such as drop tcp any any -> any any (sid:1; tcp.flags:U*;) to drop all the packets with urgent flag set.

References

https://redmine.openinfosecfoundation.org/issues/7411

Credits

Reported by Team Superflat

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVE ID

CVE-2024-55629

Weaknesses

Credits