CVE-2013-6497

What it actually does

clamscan in ClamAV before 0.98.5 crashes when the -a option processes a specially crafted input file, resulting in denial of service via local availability impact only.

Why it matters to the business

Scanning operations using the affected ClamAV version with the -a flag can be disrupted, halting malware detection workflows until the process is restarted; the issue is over a decade old with no active exploitation campaigns or ransomware use recorded.

How an attack unfolds

An attacker supplies a crafted file (such as the publicly referenced demonstration) to a clamscan invocation that includes the -a flag, triggering an unhandled condition that terminates the scanner process.

How to fix it

Upgrade ClamAV to version 0.98.5 or later; discontinue use of the -a option on unpatched versions if immediate upgrade is not feasible.

How to confirm the fix worked

Verify the installed ClamAV version is 0.98.5 or newer; attempt to scan the demonstration file with the -a flag and confirm the process no longer terminates unexpectedly.

Typical attack path

1. Obtain or craft a file that triggers the crash condition in clamscan
2. Invoke clamscan with the -a option against the file on a system running an affected version
3. Observe process termination and loss of scanning capability

How to detect it

Review clamscan process logs and system crash reports for unexpected terminations when the -a option is active; correlate with file scan events involving untrusted inputs.

What your security team should do

• Prioritize upgrade of all ClamAV instances to 0.98.5 or later
• Audit scripts and scheduled tasks for use of the -a flag and remove where unnecessary
• Monitor for any remaining legacy deployments given the 2014 publication date