CVE-2008-5539 in RISING
Summary
by MITRE
RISING Antivirus 21.06.31.00 and possibly 20.61.42.00, 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 • 10/22/2018
The vulnerability described in CVE-2008-5539 represents a significant bypass mechanism within RISING Antivirus software versions 21.06.31.00 and potentially 20.61.42.00 when operating in conjunction with Internet Explorer 6 or 7 browsers. This flaw exploits the antivirus software's file extension-based detection mechanisms, allowing malicious actors to evade security measures by manipulating the file's header information and naming conventions. The vulnerability specifically targets the heuristic analysis capabilities of the antivirus solution, demonstrating how traditional signature-based and extension-based detection methods can be circumvented through sophisticated file manipulation techniques. The MZ header, which is the standard executable file signature used by windows operating systems, when placed at the beginning of an HTML document, tricks the antivirus into misclassifying the file's true nature. This technique leverages the fact that many antivirus solutions rely heavily on file extensions to determine how to analyze and process incoming files, creating a window of opportunity for attackers to deliver malicious content.
The technical implementation of this vulnerability involves the strategic placement of an MZ header at the beginning of HTML documents, effectively mimicking executable file structures while maintaining the appearance of benign web content. When an attacker modifies the filename to remove its extension entirely or appends .txt or .jpg extensions, the antivirus system fails to properly identify the file's true executable nature. This bypass mechanism operates at the application layer, exploiting weaknesses in how the antivirus software interprets file metadata and structure. The attack vector becomes particularly dangerous when combined with existing exploits such as CVE-2006-5745, which targets vulnerabilities in internet explorer itself. The vulnerability demonstrates a classic case of insufficient input validation and file analysis logic, where the antivirus software fails to properly analyze the actual content of files rather than relying solely on superficial characteristics like file extensions. This approach aligns with common attack patterns found in the ATT&CK framework under the 'Defense Evasion' tactic, specifically targeting 'Obfuscated Files or Information' and 'Masquerading' techniques.
The operational impact of this vulnerability extends beyond simple malware delivery, as it fundamentally undermines the trust model between users and antivirus protection systems. When an antivirus solution fails to properly detect malicious content due to header manipulation, it creates a false sense of security for end users who may believe their systems are protected. The vulnerability particularly affects users running older versions of internet explorer, which were prevalent during the time this vulnerability was discovered and exploited. Organizations that relied on RISING Antivirus for protection would have been vulnerable to targeted attacks that could bypass their security measures, potentially leading to system compromise and data breaches. The effectiveness of this bypass is enhanced by the fact that many users and administrators do not fully understand the implications of file extension manipulation or the underlying file structure analysis that antivirus software should perform. This vulnerability highlights the importance of multi-layered security approaches and the dangers of over-reliance on single detection mechanisms.
Mitigation strategies for this vulnerability should focus on implementing more robust file analysis techniques that examine actual file content rather than relying solely on extensions or superficial headers. Security professionals should ensure that antivirus solutions employ comprehensive heuristic analysis and file structure examination capabilities that can identify malicious content regardless of filename or extension. The implementation of behavioral analysis and sandboxing techniques can help detect anomalous file behaviors that traditional signature-based detection might miss. Organizations should also consider updating their antivirus software to versions that have addressed this specific vulnerability, as newer iterations typically include improved detection mechanisms for such bypass techniques. Additionally, network administrators should implement additional layers of security including web application firewalls, content filtering systems, and user education programs that emphasize the dangers of downloading files with unusual extensions or from untrusted sources. This vulnerability underscores the necessity of following security best practices outlined in industry standards such as those provided by the CWE database, which categorizes this issue under improper input validation and insufficient file type checking mechanisms. The ATT&CK framework would classify this vulnerability's exploitation under defense evasion techniques, emphasizing the need for organizations to implement comprehensive security measures that can detect and prevent such sophisticated bypass methods.