CVE-2007-3952 in Norman
Summary
by MITRE
The OLE2 parsing in Norman Antivirus before 5.91.02 allows remote attackers to bypass the malware detection via a crafted DOC file, resulting from an "integer cast around".
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Analysis
by VulDB Data Team • 07/23/2019
The vulnerability identified as CVE-2007-3952 represents a critical flaw in the OLE2 file parsing mechanism of Norman Antivirus software versions prior to 5.91.02. This issue stems from improper handling of integer types during the parsing process, creating a condition that adversaries can exploit to circumvent malware detection capabilities. The vulnerability specifically affects the way the antivirus engine processes Microsoft Office document files, particularly those with the .doc extension that utilize OLE2 structured storage formats. The integer cast around problem occurs when the software attempts to convert between different integer sizes during file analysis, leading to unexpected behavior in the parsing logic. This flaw allows attackers to craft specially designed DOC files that contain malicious code or payloads, which the antivirus software fails to properly identify and neutralize due to the parsing error. The vulnerability demonstrates a classic example of improper input validation and type handling that can lead to security bypass scenarios.
The technical implementation of this vulnerability involves the manipulation of OLE2 compound document structures within Microsoft Word documents. When Norman Antivirus processes a crafted DOC file, the integer casting error occurs during the parsing of the document's internal structure, specifically in how the software handles the size and offset calculations for various OLE2 components. This improper conversion can cause the antivirus engine to skip or misinterpret critical sections of the document that would normally trigger malware detection alerts. The flaw falls under CWE-191, which addresses integer underflow and overflow conditions, and more specifically relates to CWE-194, which deals with unexpected integer truncation or extension. Attackers can exploit this by creating DOC files with carefully constructed OLE2 headers that, when processed by the vulnerable antivirus, cause the integer casting to produce values that bypass detection mechanisms entirely.
The operational impact of this vulnerability extends beyond simple malware detection failure, as it represents a fundamental weakness in the antivirus software's ability to properly analyze potentially malicious content. Organizations using affected versions of Norman Antivirus face significant risk of malware infiltration through seemingly legitimate Office documents that contain embedded malicious code. The vulnerability enables attackers to conduct targeted attacks against systems where this specific antivirus version is deployed, potentially leading to complete system compromise through document-based attacks. This type of vulnerability aligns with ATT&CK technique T1204.002, which involves user execution through spearphishing attachments, and demonstrates how weaknesses in endpoint protection can be exploited to bypass security controls. The integer casting issue creates a condition where the antivirus software's behavior becomes unpredictable when processing certain file structures, allowing malicious payloads to slip through undetected.
Mitigation strategies for CVE-2007-3952 require immediate software updates to Norman Antivirus version 5.91.02 or later, which contains the necessary fixes for the integer casting error in OLE2 parsing. System administrators should prioritize patching affected systems and verify that the updated antivirus software properly handles OLE2 compound documents without the integer conversion issues. Additionally, organizations should implement additional layers of protection including email filtering, web content filtering, and network-based intrusion detection systems to provide defense-in-depth against document-based attacks. Security monitoring should include detection of unusual file processing patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of proper input validation and type safety in security software development, emphasizing that even seemingly minor issues in parsing logic can have significant security implications. Organizations should conduct regular security assessments of their antivirus solutions to identify similar vulnerabilities in other security controls and maintain updated threat intelligence to detect potential exploitation attempts.