CVE-2024-55627

What it actually does

Unsigned integer underflow in TCP stream processing allows allocation of an extremely large buffer that is then zero-filled via memset, resulting in a buffer overflow condition during initialization.

Why it matters to the business

Compromised network monitoring and intrusion detection capabilities can allow attackers to evade detection or crash security sensors, increasing risk of undetected breaches in environments relying on Suricata for traffic analysis.

How an attack unfolds

An attacker crafts a malicious TCP stream that triggers the underflow during buffer size calculation; the resulting oversized allocation and memset operation corrupts adjacent memory, potentially enabling code execution or denial of service against the Suricata engine.

How to fix it

Upgrade Suricata to version 7.0.8 or apply the fix from commit 97e69ffb1bc2b7358115ee59f460a924893664e8; rebuild from source or obtain updated packages for affected deployments.

How to confirm the fix worked

Confirm Suricata reports version 7.0.8 or later; recompile with the referenced commit and test against known trigger streams or use static analysis to verify the underflow check is present.

Typical attack path

1. Craft and transmit a specially formed TCP stream targeting the vulnerable stream initialization path
2. Trigger the unsigned integer underflow to compute an excessively large buffer size
3. Cause memset to overwrite memory beyond intended bounds during zero-filling
4. Leverage memory corruption for arbitrary code execution or process crash

How to detect it

Inspect Suricata logs and system crash dumps for segmentation faults or abnormal memory allocation patterns during TCP stream handling; correlate with unusual inbound TCP traffic volumes around the time of any sensor instability.

What your security team should do

• Immediately upgrade all Suricata instances to the fixed version or commit
• Review network sensor placement and ensure fallback monitoring is in place during upgrades
• Monitor vendor advisories for any follow-on patches or related issues