CVE-2005-0667 in Sylpheed
Summary
by MITRE
Buffer overflow in Sylpheed before 1.0.3 and other versions before 1.9.5 allows remote attackers to execute arbitrary code via an e-mail message with certain headers containing non-ASCII characters that are not properly handled when the user replies to the message.
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Analysis
by VulDB Data Team • 07/01/2019
The vulnerability identified as CVE-2005-0667 represents a critical buffer overflow flaw in the Sylpheed email client software that existed across multiple versions prior to 1.0.3 and 1.9.5. This security weakness specifically manifests when the email client processes certain header fields containing non-ascii characters that are not adequately sanitized during the reply message generation process. The flaw falls under the category of CWE-121, which describes heap-based buffer overflow conditions where insufficient space is allocated for data manipulation, making it a prime target for exploitation by malicious actors seeking to compromise systems through crafted email messages.
The technical implementation of this vulnerability occurs during the handling of email headers that contain extended ascii characters or multi-byte sequences that exceed the allocated buffer space in Sylpheed's memory management routines. When a user attempts to reply to an email containing such malformed headers, the client's parsing mechanism fails to properly validate character boundaries and memory allocation limits, resulting in memory corruption that can be leveraged to overwrite adjacent memory locations. This particular flaw operates at the application layer and requires a user to interact with a malicious email message, specifically triggering the reply function which activates the vulnerable code path.
The operational impact of CVE-2005-0667 extends beyond simple code execution capabilities as it represents a remote code execution vulnerability that can be exploited without user interaction beyond opening or replying to a malicious message. Attackers can craft specially formatted emails containing non-ascii characters in headers such as subject lines, sender information, or other metadata fields to trigger the buffer overflow condition. The vulnerability aligns with ATT&CK technique T1190 which describes exploitation of vulnerabilities in email clients to gain unauthorized access to systems. Once successfully exploited, the attacker could potentially execute arbitrary code with the privileges of the user running the affected email client, leading to full system compromise.
Mitigation strategies for this vulnerability primarily focus on immediate software updates to versions 1.0.3 or 1.9.5 and later, which contain proper input validation and buffer management fixes. System administrators should implement email filtering mechanisms to identify and quarantine messages containing suspicious header sequences, particularly those with extended ascii characters or unusual encoding patterns. Additionally, user education regarding the dangers of opening or replying to suspicious email messages remains crucial, as the vulnerability requires user interaction to be exploited. Organizations should also consider implementing network-based intrusion detection systems that can identify patterns associated with this specific exploit attempt, and maintain regular patch management processes to ensure all email client software remains current with security fixes. The vulnerability demonstrates the importance of proper input validation and memory management in email client applications, particularly when handling international character sets and extended ascii encodings that are common in modern email communication.