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af-packet: defrag option can lead to truncated packets affecting visibility

High
victorjulien published GHSA-7m5c-cqx4-x8mp Apr 10, 2025

Package

suricata

Affected versions

< 7.0.9

Patched versions

7.0.9

Description

The AF_PACKET defrag option is enabled by default and allows AF_PACKET to re-assemble fragmented packets before reaching Suricata. However the default packet size in Suricata is based on the network interface MTU which leads to Suricata seeing truncated packets.

Impact

If using the defrag option (enabled by default) Suricata will see fragmented packets that are re-assembled to larger than 1514 byte as truncated.

Patches

Upgrade to Suricata 7.0.9, which uses better defaults and adds warnings for user configurations that may lead to issues.

Workarounds

For inline modes, disable defrag if not done already. This is recommended for inline use even after upgrading. For passive IDS mode, tpacket-v3 can be enabled with a block-size of at least 131072 bytes.

References

https://redmine.openinfosecfoundation.org/issues/7458

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-2025-29915

Weaknesses

Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data. Learn more on MITRE.