CVE-2008-5530 in Ewido Security Suite
Summary
by MITRE
Ewido Security Suite 4.0, 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 • 12/06/2017
The vulnerability described in CVE-2008-5530 represents a significant bypass mechanism within Ewido Security Suite 4.0 that exploits the interaction between antivirus software and web browsers. This flaw specifically targets the detection capabilities of the security suite when processing HTML documents through Internet Explorer versions 6 and 7, creating a pathway for malware to evade automated threat detection systems. The attack vector leverages the way security software interprets file headers and extensions to make decisions about content analysis and threat classification. The vulnerability operates by manipulating the file's metadata and presentation characteristics to confuse the antivirus detection algorithms.
The technical implementation of this vulnerability involves placing an MZ header at the beginning of an HTML document, which is the standard executable file signature used by Windows PE files. This header typically appears at the start of executable files and serves as a marker that operating systems and security tools use to identify binary executables. By inserting this signature at the beginning of an HTML document, attackers can trick the security suite into misclassifying the file content. The vulnerability is further enhanced by modifying the filename to use no extension, a .txt extension, or a .jpg extension, which are common file types that security tools may not rigorously analyze for executable content. This technique exploits the principle of file extension-based filtering and header analysis that many security solutions employ.
The operational impact of CVE-2008-5530 is substantial as it demonstrates how security software can be circumvented through simple file manipulation techniques that exploit gaps in detection logic. When Internet Explorer 6 or 7 processes these specially crafted documents, the security suite fails to properly analyze the content due to its reliance on file extension patterns and header interpretation. This creates a false sense of security for users who may believe their systems are protected against malware when in fact the security suite is bypassed through this technique. The vulnerability is particularly concerning because it specifically targets older browser versions that were widely used at the time, making it applicable to a large user base. The demonstration of this exploit using CVE-2006-5745 further illustrates how this bypass technique can be combined with other known exploits to create more sophisticated attack vectors.
This vulnerability aligns with CWE-119, which addresses weaknesses in memory handling, and relates to the broader category of input validation and sanitization issues. The flaw represents a classic case of insufficient input validation where the security suite fails to properly validate file content against expected patterns. From an ATT&CK framework perspective, this vulnerability maps to T1059.005 (Command and Scripting Interpreter: Visual Basic) and T1070.004 (Indicator Removal on Host: File Deletion) as it enables attackers to execute malicious code while evading detection mechanisms. The attack technique also aligns with T1204.002 (User Execution: Malicious File) as it relies on social engineering through file extension manipulation to trick users into executing malicious content. Organizations implementing security solutions must consider these attack patterns when designing detection rules and ensure that their systems properly validate file content regardless of extension or header characteristics.
The mitigation strategies for CVE-2008-5530 require a multi-layered approach that addresses both the immediate vulnerability and broader security practices. Security administrators should implement strict content validation mechanisms that analyze file headers and content regardless of file extensions, ensuring that security tools do not rely solely on extension-based filtering. Regular updates to security software and browser versions are essential, as newer versions typically include improved detection capabilities and address known bypass techniques. Network-based intrusion detection systems should be configured to monitor for suspicious file patterns and header combinations that may indicate attempts to exploit this vulnerability. Additionally, user education programs should emphasize the importance of not executing files with unusual extensions or from untrusted sources, even when they appear to be benign file types like text or image files. Organizations should also consider implementing application whitelisting policies that restrict execution of potentially malicious content based on content analysis rather than file extension alone.