CVE-2006-0925 in MDaemon
Summary
by MITRE
Format string vulnerability in the IMAP4rev1 server in Alt-N MDaemon 8.1.1 and possibly 8.1.4 allows remote attackers to cause a denial of service (CPU consumption) by creating and then listing folders whose names contain format string specifiers.
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Analysis
by VulDB Data Team • 09/05/2019
The CVE-2006-0925 vulnerability represents a critical format string flaw in the IMAP4rev1 server component of Alt-N MDaemon email server version 8.1.1 and potentially 8.1.4. This vulnerability resides within the server's handling of folder names during creation and listing operations, specifically when these folder names contain format string specifiers such as %s, %d, or other printf-style formatting characters. The flaw occurs because the server fails to properly sanitize or escape user-supplied folder names before processing them through format string functions, creating a dangerous condition where attacker-controlled input can be interpreted as formatting directives rather than literal text.
The technical exploitation of this vulnerability involves an attacker creating specially crafted folder names containing format string specifiers and then listing these folders through the IMAP protocol. When the server processes these folder names, it attempts to format them using standard library functions without proper input validation, causing the server to interpret the format specifiers as instructions for memory access or other operations. This misinterpretation leads to excessive cpu consumption as the server becomes trapped in processing malformed format strings, effectively causing a denial of service condition that can render the email server unavailable to legitimate users. The vulnerability is particularly dangerous because it can be exploited remotely without authentication, making it a significant threat to email server availability.
From an operational impact perspective, this vulnerability creates a substantial risk for organizations relying on MDaemon email servers, as it allows attackers to consume excessive system resources and potentially cause complete service disruption. The denial of service condition can persist until the server is manually restarted or the affected processes are terminated, creating extended downtime periods that can impact business operations. The vulnerability affects the core IMAP functionality, which is critical for email access and management, making it particularly damaging to organizations that depend heavily on email communication. Additionally, the remote exploitation capability means that attackers can target these servers from anywhere on the internet without requiring prior access credentials, amplifying the threat landscape.
Organizations should implement immediate mitigations including applying the vendor-provided patches or updates that address the format string vulnerability in MDaemon versions 8.1.1 and 8.1.4. Network-level protections such as firewall rules that restrict access to IMAP ports and implementing intrusion detection systems can help detect and prevent exploitation attempts. The vulnerability aligns with CWE-134 which specifically addresses format string vulnerabilities where format strings are constructed from user-controlled data without proper sanitization. From an attack framework perspective, this vulnerability maps to the attack technique T1499.004 within the MITRE ATT&CK framework, which covers network denial of service attacks. Regular security assessments and input validation reviews should be conducted to identify similar vulnerabilities in other server components, as format string issues often indicate broader coding security weaknesses that require comprehensive remediation strategies.