CVE-2007-3953 in Virus Control
Summary
by MITRE
The OLE2 parsing in Norman Antivirus before 5.91.02 allows remote attackers to cause a denial of service via a crafted DOC file that triggers a divide-by-zero error.
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Analysis
by VulDB Data Team • 07/23/2019
The vulnerability identified as CVE-2007-3953 represents a critical flaw in the OLE2 file parsing functionality of Norman Antivirus software prior to version 5.91.02. This issue stems from inadequate input validation within the antivirus engine's handling of Microsoft Office document formats, specifically those utilizing OLE2 (Object Linking and Embedding) structures. The vulnerability manifests when the antivirus system processes a specially crafted DOC file that contains malformed OLE2 data, leading to a system crash or complete service unavailability. The technical root cause lies in the absence of proper error handling mechanisms that would prevent division operations from occurring with zero denominators during the parsing process.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it provides attackers with a method to disrupt critical security infrastructure. When an endpoint protected by affected Norman Antivirus software encounters a maliciously crafted document, the system's parsing routine executes a division-by-zero operation that inevitably causes the antivirus service to crash. This creates a window of opportunity for attackers to bypass security controls or disrupt business operations, particularly in environments where antivirus systems serve as primary defense mechanisms. The vulnerability affects the core functionality of the antivirus engine, potentially rendering the system unable to process legitimate files or provide protection against other threats during the recovery period.
This vulnerability aligns with CWE-369, which describes the weakness of dividing by zero in software implementations, and represents a classic example of improper input validation within security software. From an ATT&CK framework perspective, this flaw maps to techniques involving service disruption and system compromise through software exploitation, potentially enabling adversaries to establish persistence or conduct more sophisticated attacks. The attack vector requires the target system to process a malicious document, making it particularly dangerous in environments where users frequently open office documents or where automatic processing of attachments occurs. The vulnerability demonstrates how security tools themselves can become attack surfaces when they fail to properly validate input from potentially malicious sources.
Mitigation strategies for CVE-2007-3953 require immediate patching of affected Norman Antivirus installations to version 5.91.02 or later, which includes corrected OLE2 parsing routines that properly handle malformed data structures. Organizations should implement additional defensive measures such as email filtering to prevent delivery of suspicious DOC files, network monitoring to detect potential exploitation attempts, and regular security assessments to identify other vulnerable components within their antivirus infrastructure. System administrators should also consider implementing network segmentation to limit the impact of potential exploitation, ensuring that antivirus systems cannot be easily leveraged as entry points for broader network compromise. The vulnerability underscores the critical importance of maintaining up-to-date security software and implementing layered defensive strategies to protect against both known and emerging threats.