CVE-2018-14359 in Mutt
Summary
by MITRE
An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. They have a buffer overflow via base64 data.
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Analysis
by VulDB Data Team • 04/09/2023
The vulnerability identified as CVE-2018-14359 represents a critical buffer overflow flaw affecting the Mutt and NeoMutt email clients prior to specific version releases. This issue stems from inadequate input validation during the processing of base64 encoded data within the email parsing functionality. The flaw exists in the way these email clients handle decoded base64 content, where insufficient boundary checks allow maliciously crafted base64 data to overwrite adjacent memory regions. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter usage in exploitation contexts. The buffer overflow occurs when the application attempts to decode base64 content without proper bounds checking, potentially leading to arbitrary code execution or application crashes.
The technical implementation of this vulnerability involves the base64 decoding routines within the email processing pipeline where the application allocates fixed-size buffers for decoded data without validating the actual size requirements. When processing maliciously constructed base64 encoded attachments or embedded content, the decoding process can write beyond the allocated buffer boundaries, corrupting adjacent memory structures. This memory corruption can potentially overwrite return addresses, function pointers, or other critical program state information, enabling attackers to redirect execution flow or inject malicious code. The vulnerability is particularly dangerous because base64 encoding is commonly used in email attachments and embedded content, making it a frequent attack vector. The flaw affects both Mutt and NeoMutt clients, with specific version thresholds of Mutt 1.10.1 and NeoMutt 2018-07-16 indicating when the fix was implemented.
From an operational impact perspective, this vulnerability creates significant security risks for users who process email content from untrusted sources. Attackers can craft specially formatted emails containing malicious base64 data that, when opened by vulnerable email clients, triggers the buffer overflow condition. The exploitation can result in complete system compromise if successful, as the overflow allows for arbitrary code execution with the privileges of the affected user. Email administrators face the challenge of protecting users across multiple platforms where these email clients are deployed, including desktop environments, mobile devices, and server-based email systems. The vulnerability affects organizations that rely on these email clients for business communications, potentially exposing sensitive data and enabling persistent access to target systems. Organizations using these clients without proper patch management protocols remain at risk of exploitation, particularly in environments where email processing occurs automatically without user interaction.
Mitigation strategies for CVE-2018-14359 primarily focus on immediate patching of affected systems to versions containing the necessary security fixes. System administrators should prioritize updating Mutt and NeoMutt installations to versions 1.10.1 or later for Mutt and the corresponding NeoMutt release from 2018-07-16 or later. Additionally, implementing email filtering mechanisms that scan for suspicious base64 content and implementing sandboxing techniques for email processing can provide defense-in-depth measures. Network administrators should consider deploying email security appliances that can detect and block malicious base64 encoded content before it reaches user systems. Organizations should also implement user education programs to raise awareness about the risks of opening unsolicited email attachments, particularly those containing encoded content. The fix typically involves implementing proper bounds checking during base64 decoding operations and ensuring that allocated buffers can accommodate the maximum possible decoded data size. Security monitoring should include detection of unusual email processing patterns that might indicate exploitation attempts, and regular vulnerability assessments should verify that all email client installations remain up to date with security patches.