Rule Category

FILE-OTHER -- Snort detected traffic targeting vulnerabilities in a file type that does not require enough rule coverage to have its own category.

Alert Message

FILE-OTHER Libmspack cabd_sys_read_block off-by-one heap overflow attempt

Rule Explanation

This event is generated when a cab file that triggers an off-by-one heap overflow in Libmspack is observed. Impact: Potential Code Execution Details: A crafted cab file can trigger an off-by-one heap overflow in Libmspack cabd_sys_read_block by sending a file with a cbData value of 38912 or greater within the CFDATA block. Ease of Attack:

What To Look For

Known Usage

No public information

False Positives

No known false positives


Cisco Talos Intelligence Group

MITRE ATT&CK Framework



For reference, see the MITRE ATT&CK vulnerability types here:


Additional Links

Rule Vulnerability

CVE Additional Information

In mspack/cab.h in libmspack before 0.8alpha and cabextract before 1.8, the CAB block input buffer is one byte too small for the maximal Quantum block, leading to an out-of-bounds write.
Severity Base Score6.5
Impact Score3.6 Exploit Score2.8
Confidentiality ImpactNONE Integrity ImpactNONE
Availability ImpactHIGH Attack VectorNETWORK
Authentication Ease of AccessLOW
Privileges RequiredNONE