CVE-2008-5514 in IMAP
Summary
by MITRE
Off-by-one error in the rfc822_output_char function in the RFC822BUFFER routines in the University of Washington (UW) c-client library, as used by the UW IMAP toolkit before imap-2007e and other applications, allows context-dependent attackers to cause a denial of service (crash) via an e-mail message that triggers a buffer overflow.
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Analysis
by VulDB Data Team • 05/29/2025
The vulnerability identified as CVE-2008-5514 represents a critical off-by-one error within the rfc822_output_char function of the University of Washington c-client library's RFC822BUFFER routines. This flaw exists in the UW IMAP toolkit version prior to imap-2007e and affects numerous applications that rely on this library for email processing. The vulnerability stems from improper boundary checking during character output operations, creating a condition where buffer overflow can occur when processing specially crafted email messages. The issue is classified as context-dependent, meaning that exploitation requires specific conditions related to the email content being processed, making it particularly challenging to detect and prevent through automated means.
The technical implementation of this vulnerability manifests when the rfc822_output_char function fails to properly validate buffer boundaries during character processing operations. When an email message contains specific character sequences or formatting that triggers the flawed buffer management logic, the function attempts to write beyond allocated memory boundaries. This off-by-one error creates a scenario where one additional byte is written beyond the intended buffer limits, causing memory corruption that ultimately leads to application crash. The flaw operates at the level of email parsing and formatting, specifically within the RFC822 message structure handling components that are fundamental to email client functionality. This type of vulnerability falls under CWE-129, which specifically addresses improper validation of the length of input buffers, and represents a classic example of memory safety issues in C-based applications.
The operational impact of CVE-2008-5514 extends beyond simple denial of service, as it can be leveraged by malicious actors to disrupt email services and potentially escalate to more severe attacks. When exploited, the vulnerability causes applications using the affected UW c-client library to crash, resulting in service disruption for legitimate users. Email servers and clients that process incoming messages through this library become vulnerable to targeted attacks where attackers can craft specific email payloads designed to trigger the buffer overflow condition. The attack vector requires the target application to process the malicious email message, making it a server-side vulnerability that can be exploited through email injection attacks. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a significant risk to email infrastructure security. The impact is particularly severe in environments where email services are critical to business operations, as the vulnerability can be used to systematically disrupt email availability.
Mitigation strategies for CVE-2008-5514 require immediate patching of affected systems and implementation of proper input validation measures. Organizations should prioritize updating to UW IMAP toolkit version 2007e or later, which contains the necessary fixes for the buffer overflow condition. Additionally, administrators should implement email filtering rules that can detect and quarantine suspicious message patterns that might trigger the vulnerability. Network-level protections can include implementing rate limiting and connection restrictions on email servers to reduce the effectiveness of automated exploitation attempts. The vulnerability highlights the importance of proper buffer management in C-based applications and underscores the need for comprehensive code review processes that include boundary checking and memory safety validation. Security teams should also consider implementing intrusion detection systems that can monitor for unusual email processing patterns that might indicate exploitation attempts, while maintaining regular vulnerability assessments to identify other potential buffer overflow conditions in legacy email processing components.