CVE-2021-44143 : Security Advisory and Response

A flaw was found in mbsync in isync 1.4.0 through 1.4.3 that could potentially lead to a heap overflow vulnerability allowing for remote code execution.

Understanding CVE-2021-44143

What is CVE-2021-44143?

CVE-2021-44143 is a vulnerability in mbsync in isync versions 1.4.0 through 1.4.3, where a malicious or compromised IMAP server could exploit it to trigger a heap overflow.

The Impact of CVE-2021-44143

The vulnerability could be exploited by a remote attacker to execute arbitrary code on the target system.

Technical Details of CVE-2021-44143

Vulnerability Description

The flaw in mbsync in isync versions 1.4.0 through 1.4.3 allows a malicious or compromised IMAP server to provoke a heap overflow by using a specially crafted mail message without headers.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions: isync 1.4.0 through 1.4.3

Exploitation Mechanism

An attacker sends a crafted mail message lacking headers to the vulnerable mbsync component
By starting the message with an empty line, a heap overflow is triggered

Mitigation and Prevention

Immediate Steps to Take

Update isync to a non-vulnerable version
Consider blocking malicious email servers

Long-Term Security Practices

Regularly update software and apply security patches
Implement email security best practices

Patching and Updates

Apply patches provided by the isync project to address the vulnerability