CVE-2012-2124 in Red Hat
Summary
by MITRE
functions/imap_general.php in SquirrelMail, as used in Red Hat Enterprise Linux (RHEL) 4 and 5, does not properly handle 8-bit characters in passwords, which allows remote attackers to cause a denial of service (disk consumption) by making many IMAP login attempts with different usernames, leading to the creation of many preference files. NOTE: this issue exists because of an incorrect fix for CVE-2010-2813.
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Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2012-2124 represents a significant security flaw in SquirrelMail's IMAP general functions implementation, specifically within the functions/imap_general.php file. This issue affects Red Hat Enterprise Linux versions 4 and 5, where the software fails to properly manage 8-bit characters contained within user passwords during authentication processes. The flaw stems from an erroneous remediation approach for a previous vulnerability, CVE-2010-2813, which created a new attack vector that adversaries can exploit to disrupt system operations.
The technical mechanism behind this vulnerability involves the improper handling of multibyte character sequences in password inputs during IMAP authentication attempts. When users attempt to log in with passwords containing 8-bit characters, the system fails to correctly process these inputs, leading to the creation of numerous preference files on the filesystem. Each failed authentication attempt with different usernames generates additional preference files, causing exponential disk space consumption. This behavior occurs because the application does not properly sanitize or validate the character encoding of password inputs, resulting in malformed file creation processes that accumulate over time.
The operational impact of this vulnerability extends beyond simple resource exhaustion, creating potential denial of service conditions that can severely impact system availability. Attackers can systematically consume disk space by repeatedly attempting IMAP logins with varying usernames and password combinations containing 8-bit characters, effectively exhausting available storage capacity. This attack vector can be particularly damaging in environments where disk space monitoring is minimal or where automated systems rely on consistent storage availability for proper operation. The vulnerability also demonstrates poor input validation practices that could potentially enable additional attack surfaces beyond simple denial of service.
Security professionals should recognize this issue as a variant of CWE-180, which addresses incorrect behavior in input validation, and it aligns with ATT&CK technique T1499.001 for resource exhaustion attacks. The improper handling of character encoding in authentication flows represents a fundamental flaw in application security design that requires immediate attention. Organizations should implement rate limiting mechanisms to prevent excessive authentication attempts, establish monitoring for unusual disk space consumption patterns, and ensure that all authentication systems properly validate and sanitize input character sets before processing. Additionally, the vulnerability highlights the importance of thorough regression testing when implementing security patches to prevent introducing new weaknesses that may be exploited by adversaries.
The remediation approach should focus on proper character encoding validation within the IMAP authentication functions, ensuring that 8-bit character sequences are appropriately handled or rejected during password processing. System administrators should apply the appropriate security updates from Red Hat, which would contain the corrected implementation for handling multibyte characters in authentication contexts. Regular security audits of authentication systems should be conducted to identify similar encoding vulnerabilities that could potentially create similar denial of service conditions. The incident also underscores the need for comprehensive testing of security patches to ensure that fixes for one vulnerability do not inadvertently create new attack vectors that can be exploited by malicious actors.