CVE-2021-28429 : Exploit Details and Defense Strategies

A detailed overview of CVE-2021-28429, an integer overflow vulnerability in FFmpeg version 4.3.2 that could lead to a denial of service attack via a crafted .mov file.

Understanding CVE-2021-28429

This section delves into the specifics of the vulnerability, its impact, affected systems, exploitation mechanism, and mitigation strategies.

What is CVE-2021-28429?

The CVE-2021-28429 is an integer overflow vulnerability found in av_timecode_make_string in libavutil/timecode.c within FFmpeg version 4.3.2. This flaw may be exploited by local attackers to trigger a denial of service (DoS) attack by utilizing a specially crafted .mov file.

The Impact of CVE-2021-28429

The impact of this vulnerability is significant as it allows malicious actors to cause a denial of service condition on affected systems, disrupting normal operations and potentially leading to system crashes or unresponsiveness.

Technical Details of CVE-2021-28429

This section provides more in-depth technical insights into the vulnerability, including its description, affected systems, affected versions, and the exploitation mechanism.

Vulnerability Description

The vulnerability arises from an integer overflow issue within the av_timecode_make_string function in libavutil/timecode.c, which can be exploited through a specifically crafted .mov file to trigger a DoS condition on the target system.

Affected Systems and Versions

The affected system includes FFmpeg version 4.3.2. The specific versions and products affected by this vulnerability, other than FFmpeg 4.3.2, are not disclosed.

Exploitation Mechanism

Attackers can exploit this vulnerability by creating a malicious .mov file that triggers the integer overflow in the av_timecode_make_string function, thereby causing a denial of service condition on the local system.

Mitigation and Prevention

This section outlines the steps that organizations and users can take to mitigate the risk posed by CVE-2021-28429 and prevent potential exploitation.

Immediate Steps to Take

To address this vulnerability, users are advised to update FFmpeg to a non-vulnerable version and exercise caution when handling .mov files from untrusted sources. Additionally, implementing strict file validation mechanisms can help prevent malicious exploitation.

Long-Term Security Practices

In the long term, maintaining up-to-date software versions, monitoring security advisories for patch releases, and conducting regular security audits can enhance the overall security posture of the system and mitigate similar vulnerabilities.

Patching and Updates

It is crucial for users to apply security patches released by FFmpeg promptly to address CVE-2021-28429. Regularly updating software ensures that known vulnerabilities are mitigated, reducing the risk of exploitation.