CVE-2008-5524 in Cat Quickheal
Summary
by MITRE
CAT-QuickHeal 10.00 and possibly 9.50, when Internet Explorer 6 or 7 is used, allows remote attackers to bypass detection of malware in an HTML document by placing an MZ header (aka "EXE info") at the beginning, and modifying the filename to have (1) no extension, (2) a .txt extension, or (3) a .jpg extension, as demonstrated by a document containing a CVE-2006-5745 exploit.
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Analysis
by VulDB Data Team • 11/30/2017
The vulnerability described in CVE-2008-5524 represents a significant bypass mechanism within CAT-QuickHeal antivirus software versions 9.50 and 10.00, specifically when operating in conjunction with Internet Explorer 6 or 7 browsers. This flaw exploits the software's content inspection methodology by manipulating file headers and extensions to evade detection systems. The attack vector specifically targets the heuristic analysis capabilities of the antivirus solution, demonstrating how improper file type identification can lead to critical security gaps in malware detection.
The technical implementation of this vulnerability relies on the manipulation of executable file headers within HTML documents. By placing an MZ header - which is the standard marker for executable files in windows operating systems - at the beginning of an HTML document, attackers can trick the antivirus software into misclassifying the file type. This technique exploits the fact that QuickHeal's detection algorithms may prioritize filename extensions over actual file content when determining threat assessment. The vulnerability becomes operational when the filename is modified to lack an extension entirely, or to use .txt or .jpg extensions, effectively bypassing the software's signature-based and heuristic detection mechanisms.
The operational impact of this vulnerability extends beyond simple malware evasion to represent a fundamental flaw in how the antivirus solution processes and analyzes file content. When combined with known exploits such as CVE-2006-5745, this vulnerability creates a dangerous attack scenario where malicious actors can deliver payloads that would otherwise be detected by standard antivirus measures. The implications are particularly severe given that the affected versions of QuickHeal were widely deployed in enterprise environments, potentially allowing attackers to establish persistent threats within networks. This vulnerability aligns with CWE-119 which addresses improper restriction of operations within a memory buffer, and represents a specific case where the buffer's boundaries are incorrectly defined based on file extension rather than actual content analysis.
The mitigation strategies for this vulnerability require immediate software updates from QuickHeal to address the flawed detection logic, along with network-level controls to monitor and restrict access to suspicious file types. Organizations should implement additional security measures including content filtering, application whitelisting, and enhanced endpoint protection to compensate for the temporary vulnerability. The ATT&CK framework categorizes this as a technique involving "Masquerading" and "Obfuscated Files or Information" where attackers manipulate file properties to avoid detection. Security administrators should also consider implementing file type validation at multiple network layers and ensure that antivirus solutions perform comprehensive content analysis regardless of file extension. This vulnerability underscores the critical importance of robust file type identification and content analysis in modern cybersecurity defenses, particularly in environments where legacy browser support is required. The incident highlights the necessity for antivirus vendors to implement more sophisticated detection algorithms that cannot be easily bypassed through simple file property manipulation techniques.