CVE-2006-6291 in MailEnable Enterprise
Summary
by MITRE
Stack overflow in the IMAP module (MEIMAPS.EXE) in MailEnable Professional 1.6 through 1.83 and 2.0 through 2.33, and MailEnable Enterprise 1.1 through 1.40 and 2.0 through 2.33, allows remote authenticated users to cause a denial of service (crash) via a long argument containing * (asterisk) and ? (question mark) characters to the DELETE command, as addressed by the ME-10020 hotfix.
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Analysis
by VulDB Data Team • 07/11/2019
The vulnerability described in CVE-2006-6291 represents a critical stack overflow condition within the IMAP module of MailEnable email server software. This flaw exists in multiple versions of both MailEnable Professional and Enterprise editions, specifically affecting versions 1.6 through 1.83 and 2.0 through 2.33 for Professional, and 1.1 through 1.40 and 2.0 through 2.33 for Enterprise. The vulnerability manifests when the MEIMAPS.EXE process receives a specially crafted DELETE command containing asterisk and question mark characters, creating a condition that leads to memory corruption and subsequent system instability.
The technical implementation of this vulnerability involves improper input validation within the IMAP protocol handler, specifically in how it processes the DELETE command with malformed arguments. When an authenticated user sends a DELETE command containing extended wildcards such as asterisks and question marks, the application fails to properly sanitize or limit the length of these arguments before processing them through stack-based operations. This lack of proper boundary checking creates an exploitable condition where the stack buffer can be overwritten with excessive data, leading to memory corruption and ultimately causing the application to crash.
From an operational perspective, this vulnerability presents a significant risk to email server availability and reliability. The attack requires only authenticated access to the system, meaning that legitimate users with valid credentials can trigger the denial of service condition. This makes the vulnerability particularly dangerous in environments where email services are critical to business operations, as unauthorized users could potentially disrupt email communications. The impact extends beyond simple service interruption, as the crash could result in data loss or require system administrators to restart services manually, potentially affecting legitimate email users during critical business periods.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in network protocol implementations. According to ATT&CK framework, this vulnerability maps to T1499.004 for network denial of service and T1595.001 for network scanning techniques that could be used to identify vulnerable systems. The presence of a specific hotfix (ME-10020) indicates that the vendor recognized the severity of this issue and provided a targeted solution to address the buffer overflow condition in the IMAP module. Organizations should prioritize applying this hotfix immediately and implement additional monitoring for unusual authentication patterns or potential exploitation attempts targeting the IMAP service.
Mitigation strategies should include immediate deployment of the vendor-provided hotfix ME-10020, followed by comprehensive network monitoring to detect potential exploitation attempts. System administrators should also consider implementing network segmentation to limit access to the IMAP service and establish robust logging mechanisms to track authenticated sessions. Regular vulnerability assessments and penetration testing should be conducted to identify similar buffer overflow conditions in other email server components. Additionally, organizations should maintain updated inventory records of all MailEnable installations to ensure complete remediation across their infrastructure and consider implementing intrusion detection systems that can identify suspicious DELETE command patterns containing wildcard characters.