CVE-2021-39589

What it actually does

A NULL pointer dereference in parse_metadata() within abc.c causes the application to crash when processing a specially crafted input file.

Why it matters to the business

Processing malicious files with swftools can cause the tool to crash, leading to denial of service for any automated workflows or scripts relying on it.

How an attack unfolds

An attacker crafts a malicious SWF file containing malformed ABC metadata. When the victim uses swftools to process the file (e.g., via a command-line tool), the parse_metadata function dereferences a NULL pointer, crashing the application.

How to fix it

The vulnerability remains unpatched in the last known version; consider alternative tools or isolating usage of swftools when handling untrusted files.

How to confirm the fix worked

Attempt to process a known malicious test file and observe for crashes; verify software version is newer than the affected release.

Typical attack path

1. Craft a malicious input file with malformed metadata
2. Deliver the file to the target environment
3. Trick the user or automated process into processing the file with swftools
4. Trigger NULL pointer dereference leading to crash

How to detect it

Look for crashes or segmentation faults in swftools processes in system logs when processing SWF files.

What your security team should do

• Avoid processing untrusted SWF files with swftools
• Implement sandboxing for any file processing tools
• Monitor project for patches