CVE-2008-6922 in CMailServer
Summary
by MITRE
Multiple stack-based buffer overflows in CMailCOM.dll in CMailServer 5.4.6 allow remote attackers to execute arbitrary code via a long argument to the (1) CreateUserPath, (2) Logout, (3) DeleteMailByUID, (4) MoveToInbox, (5) MoveToFolder, (6) DeleteMailEx, (7) GetMailDataEx, (8) SetReplySign, (9) SetForwardSign, and (10) SetReadSign methods, which are not properly handled by (a) the POP3 Class ActiveX control (CMailCom.POP3); or a long argument to the (11) AddAttach, (12) SetSubject, (13) SetBcc, (14) SetBody, (15) SetCc, (16) SetFrom, (17) SetTo, and (18) SetFromUID methods, which are not properly handled by the Class ActiveX control (CMailCOM.SMTP), as demonstrated via the indexOfMail parameter to mwmail.asp.
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Analysis
by VulDB Data Team • 10/31/2024
The vulnerability described in CVE-2008-6922 represents a critical stack-based buffer overflow issue affecting CMailServer 5.4.6 through its CMailCOM.dll component. This flaw exists within the ActiveX controls that handle email processing operations, specifically impacting both POP3 and SMTP functionality through the CMailCom.POP3 and CMailCOM.SMTP classes respectively. The vulnerability stems from inadequate input validation and boundary checking mechanisms within the email server's ActiveX controls, which fail to properly sanitize user-supplied arguments before processing them in memory.
The technical exploitation of this vulnerability occurs when remote attackers provide excessively long argument strings to specific methods within the CMailCOM.dll library. The affected methods span across multiple email operations including CreateUserPath, Logout, DeleteMailByUID, MoveToInbox, MoveToFolder, DeleteMailEx, GetMailDataEx, SetReplySign, SetForwardSign, and SetReadSign for the POP3 control, while the SMTP control is affected by AddAttach, SetSubject, SetBcc, SetBody, SetCc, SetFrom, SetTo, and SetFromUID methods. These methods are particularly dangerous because they handle user input directly without proper bounds checking, allowing attackers to overwrite adjacent memory locations on the stack.
The operational impact of this vulnerability is severe as it provides remote attackers with the ability to execute arbitrary code on the affected system with the privileges of the user running the CMailServer service. This represents a privilege escalation vulnerability that can be exploited without authentication, potentially leading to complete system compromise. The attack vector involves sending specially crafted malformed arguments to the vulnerable ActiveX methods through web-based interfaces, specifically demonstrated via the mwmail.asp page that handles the indexOfMail parameter. The stack-based buffer overflow allows attackers to overwrite return addresses and function pointers, enabling code execution control.
From a cybersecurity perspective, this vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in software security architecture. The attack pattern aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, as the exploitation typically involves web-based scripting to deliver malicious input to the vulnerable ActiveX controls. The vulnerability also demonstrates characteristics of T1505.003 Server Software Component: Web Shell, as the compromised system could be used to establish persistent access through the executed malicious code.
Mitigation strategies for this vulnerability require immediate patching of the CMailServer 5.4.6 software to the latest available version that addresses these buffer overflow conditions. Organizations should implement network segmentation to limit access to the vulnerable email server, disable unnecessary ActiveX controls, and deploy web application firewalls to filter malicious input parameters. Input validation should be strengthened at multiple layers including application-level sanitization, parameterized queries, and proper error handling to prevent buffer overflow conditions. Additionally, system monitoring should be enhanced to detect unusual network traffic patterns or code execution attempts that may indicate exploitation attempts. The vulnerability highlights the importance of secure coding practices and proper input validation in ActiveX controls, particularly when handling user-supplied data in server-side applications.