CVE-2021-42196

What it actually does

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

Why it matters to the business

Attackers can crash the application, disrupting any workflows that rely on processing SWF files and potentially causing service interruptions or loss of productivity.

How an attack unfolds

An attacker crafts a malicious SWF file that triggers the NULL pointer dereference in traits_parse() when parsed by swftools, causing the application to crash when a user processes the file locally.

How to fix it

Upgrade swftools to a version released after 20201222 once a fix is available from the project maintainers, or replace the tool with a maintained alternative for SWF processing.

How to confirm the fix worked

Rebuild or reinstall from a patched source, then verify that processing of sample SWF files no longer results in a crash in traits_parse(); inspect abc.c to confirm the dereference has been addressed.

Typical attack path

1. Craft a malicious SWF file that triggers the NULL pointer dereference in traits_parse()
2. Deliver the crafted file to the target environment
3. Induce the victim to open the file using the affected swftools binary
4. Trigger application crash resulting in denial of service

How to detect it

Review system and application logs for swftools crashes, segmentation faults, or signals originating from abc.c or the traits_parse function when SWF files are processed.

What your security team should do

• Restrict swftools usage to trusted files only until a fix is released
• Evaluate and migrate to supported SWF processing libraries or tools
• Monitor the swftools project repository for upstream patches and apply them promptly