CVE-2007-2187 in eXtremail
Summary
by MITRE
Stack-based buffer overflow in eXtremail 2.1.1 and earlier allows remote attackers to execute arbitrary code via a long DNS response. NOTE: this might be related to CVE-2006-6926.
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Analysis
by VulDB Data Team • 09/07/2024
The vulnerability identified as CVE-2007-2187 represents a critical stack-based buffer overflow flaw in eXtremail version 2.1.1 and earlier installations. This security defect resides within the email server software's handling of DNS responses, creating a remote code execution vector that adversaries can exploit from outside the target network. The vulnerability stems from insufficient input validation when processing DNS query results, specifically failing to properly bounds-check the length of incoming DNS response data before storing it in a fixed-size stack buffer. This oversight creates a condition where maliciously crafted DNS responses can overwrite adjacent stack memory, potentially allowing attackers to overwrite return addresses and execute arbitrary code with the privileges of the affected service process.
The technical implementation of this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which occurs when data is written to a buffer located on the stack without proper bounds checking. In eXtremail's case, the software processes DNS responses during email delivery operations, particularly when resolving domain names for mail routing. When a remote attacker crafts a DNS response containing excessive data, the application fails to validate the response length against the allocated buffer space, resulting in memory corruption that can be leveraged for exploitation. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1059.007 Command and Scripting Interpreter: PowerShell, as the successful exploitation would likely involve executing malicious code through the compromised email server process, potentially leading to full system compromise.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with persistent access to email infrastructure that can be used for various malicious activities including data exfiltration, spam distribution, and as a foothold for further network infiltration. Email servers are often critical infrastructure components that handle sensitive communications, making them attractive targets for attackers seeking to establish long-term access or conduct advanced persistent threats. The remote nature of the attack means that exploitation can occur without requiring physical access to the target system, making detection and prevention more challenging. Organizations running affected versions of eXtremail face significant risk of unauthorized access, data breaches, and potential compromise of their entire email infrastructure. The vulnerability's relationship to CVE-2006-6926 suggests a pattern of similar buffer overflow issues in the same software family, indicating that the development team may have failed to implement comprehensive input validation across multiple components. This type of vulnerability typically requires immediate patching or mitigation, as the window for exploitation is often minimal and the consequences severe, with potential for complete system compromise and data loss.