CVE-2020-16094 : Exploit Details and Defense Strategies

Claws Mail through 3.17.6 is vulnerable to a stack consumption issue due to unlimited recursion in imap_scan_tree_recursive.

Understanding CVE-2020-16094

In this CVE, a malicious IMAP server can exploit a flaw in Claws Mail, potentially leading to stack consumption.

What is CVE-2020-16094?

This CVE refers to a vulnerability in Claws Mail versions up to 3.17.6, where an attacker-controlled IMAP server can cause excessive stack usage by triggering unlimited recursion during the folder tree reconstruction process.

The Impact of CVE-2020-16094

The vulnerability allows a remote attacker to exhaust the stack memory of the affected application, potentially leading to a denial of service (DoS) condition or arbitrary code execution.

Technical Details of CVE-2020-16094

Claws Mail's imap_scan_tree_recursive function is susceptible to exploitation due to improper handling of recursive calls.

Vulnerability Description

The issue arises from unbounded recursion into subdirectories during the folder tree rebuild process.

Affected Systems and Versions

Claws Mail versions up to 3.17.6 are impacted by this vulnerability.

Exploitation Mechanism

A malicious IMAP server can exploit this flaw by sending specially crafted requests that trigger excessive recursion, leading to stack exhaustion.

Mitigation and Prevention

Taking immediate action and implementing long-term security measures are crucial to mitigate the risks associated with CVE-2020-16094.

Immediate Steps to Take

Update Claws Mail to the latest version to patch the vulnerability.
Avoid connecting to untrusted or potentially malicious IMAP servers.

Long-Term Security Practices

Regularly monitor and update software to address security vulnerabilities promptly.
Implement network security measures to detect and block malicious traffic targeting IMAP services.

Patching and Updates

Apply patches and updates provided by Claws Mail to fix the vulnerability and enhance the security of the application.