CVE-2000-1197 in IMAP
Summary
by MITRE
POP2 or POP3 server (pop3d) in imap-uw IMAP package on FreeBSD and other operating systems creates lock files with predictable names, which allows local users to cause a denial of service (lack of mail access) for other users by creating lock files for other mail boxes.
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Analysis
by VulDB Data Team • 07/08/2014
The vulnerability described in CVE-2000-1197 represents a significant security flaw in the pop3d component of the imap-uw IMAP package that affects FreeBSD and similar operating systems. This issue stems from the predictable naming convention used for lock files that the POP2 and POP3 servers create during mail access operations. When local users exploit this vulnerability, they can deliberately create lock files with the same predictable names that the legitimate mail server would use, effectively blocking other users from accessing their mailboxes.
The technical implementation of this vulnerability involves the improper handling of file locking mechanisms within the mail server software. The pop3d service generates lock files to prevent concurrent access to mailboxes, but these lock files follow a predictable naming pattern that makes them easily exploitable by malicious local users. This predictable naming scheme violates fundamental security principles regarding file system access controls and resource management. According to CWE-362, this represents a concurrent execution condition that allows a race condition to occur, where the vulnerability stems from insufficient synchronization mechanisms. The flaw directly enables a denial of service attack by preventing legitimate users from accessing their mail accounts, effectively creating a lockout scenario that impacts system usability.
The operational impact of this vulnerability extends beyond simple service disruption as it creates a persistent access control issue within the mail server environment. Local users who exploit this vulnerability can systematically prevent other legitimate users from accessing their mailboxes, leading to significant productivity losses and potential business disruption. The attack vector is particularly concerning because it requires minimal privileges and can be executed by any local user with access to the system. This vulnerability falls under the ATT&CK technique T1499.004, which describes the use of denial of service attacks to disrupt services, specifically targeting the availability of mail services. The impact is not limited to individual mail access but can potentially cascade across multiple users if the vulnerability is exploited systematically.
Mitigation strategies for this vulnerability should focus on implementing proper file locking mechanisms with unpredictable naming conventions and ensuring that lock files are created with appropriate permissions. System administrators should consider upgrading to patched versions of the imap-uw package where the lock file naming has been made unpredictable and secure. Additionally, implementing proper access controls and monitoring for unauthorized lock file creation can help detect exploitation attempts. The solution must address the root cause by ensuring that lock file generation uses secure randomization techniques rather than predictable patterns, which aligns with security best practices outlined in various industry standards and guidelines for secure system design.