CVE-2010-1677 in MHonArc
Summary
by MITRE
MHonArc 2.6.16 allows remote attackers to cause a denial of service (CPU consumption) via start tags that are placed within other start tags, as demonstrated by a <bo<bo<bo<bo<body>dy>dy>dy>dy> sequence, a different vulnerability than CVE-2010-4524.
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Analysis
by VulDB Data Team • 10/29/2024
The vulnerability identified as CVE-2010-1677 affects MHonArc version 2.6.16, a widely used email archiving and formatting tool that processes email messages into HTML format for web browsing. This particular flaw represents a denial of service condition that specifically targets the parser's handling of nested HTML start tags, creating an exploitable scenario where malicious input can cause excessive CPU consumption on affected systems. The vulnerability demonstrates a classic parsing error where the software fails to properly handle malformed HTML sequences that contain nested start tags, leading to resource exhaustion during processing operations. The specific attack vector involves crafting HTML sequences where start tags are embedded within other start tags, as exemplified by the sequence <bo<bo<bo<bo<body>dy>dy>dy>dy> which creates a parsing loop that consumes disproportionate computational resources.
The technical implementation of this vulnerability stems from the parser's inadequate handling of nested HTML tag structures during the processing of email content. When MHonArc encounters the malformed sequence where <bo<bo<bo<bo<body>dy>dy>dy>dy>, the parser attempts to recursively process each nested start tag without proper bounds checking or termination conditions. This leads to an exponential increase in processing time and CPU utilization as the parser attempts to resolve the malformed structure, ultimately causing the system to become unresponsive or consume all available processing power. The vulnerability operates at the application layer and represents a form of resource exhaustion attack that can be executed remotely without requiring authentication or elevated privileges. This parsing flaw aligns with CWE-129, which describes improper validation of input boundaries, and demonstrates how malformed input can lead to denial of service conditions through improper resource management.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise system availability and performance across email archiving environments. Organizations relying on MHonArc for email management may experience complete service outages when maliciously crafted emails are processed, particularly in high-volume email environments where the parser handles thousands of messages per hour. The vulnerability can be exploited by attackers to launch sustained denial of service attacks against email servers or archiving systems, making it particularly dangerous in environments where email availability is critical. Systems running vulnerable versions of MHonArc may experience complete system slowdowns or crashes, affecting not only email archiving but potentially other services that depend on the underlying system resources. The attack requires no specialized tools or privileges, making it accessible to a broad range of threat actors and increasing the likelihood of successful exploitation in production environments.
Mitigation strategies for CVE-2010-1677 should focus on immediate patching of affected systems, as the vulnerability represents a critical security flaw that can be exploited for denial of service attacks. Organizations should upgrade to MHonArc versions that address this specific parsing vulnerability, as the original 2.6.16 release contains no built-in protections against nested tag exploitation. Network-level protections can include implementing input validation filters that detect and block malformed HTML sequences before they reach the parser, though this approach may impact legitimate email processing. Additionally, system administrators should implement resource monitoring and limiting mechanisms to prevent single processes from consuming excessive CPU resources, using techniques such as process priority adjustments or CPU capping to limit the impact of potential exploitation. The vulnerability also highlights the importance of proper input sanitization and boundary checking in web applications, aligning with ATT&CK technique T1499.004 for resource exhaustion attacks. Organizations should also consider implementing email filtering solutions that can identify and quarantine potentially malicious email content before it reaches the archiving system, reducing the attack surface and providing additional layers of defense against similar vulnerabilities.