CVE-2007-6189 in Online Anti-Virus Scanner
Summary
by MITRE
A certain ActiveX control in (1) OScan8.ocx and (2) Oscan81.ocx in BitDefender Online Anti-Virus Scanner 8.0 allows remote attackers to execute arbitrary code via a long argument to the InitX method that begins with a "%%" sequence, which is misinterpreted as a Unicode string and decoded twice, leading to improper memory allocation and a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 10/12/2024
The vulnerability identified as CVE-2007-6189 represents a critical heap-based buffer overflow in BitDefender Online Anti-Virus Scanner version 8.0, specifically affecting two ActiveX controls named OScan8.ocx and Oscan81.ocx. This flaw exists within the InitX method of these components, creating a dangerous condition where remote attackers can execute arbitrary code on vulnerable systems. The vulnerability stems from improper input validation and memory handling within the ActiveX control architecture, making it particularly dangerous in web-based attack scenarios where users might unknowingly interact with malicious content.
The technical exploitation mechanism involves crafting a specially formatted argument string that begins with a "%%" sequence, which the vulnerable ActiveX control interprets as a Unicode string. This initial interpretation causes the system to decode the sequence twice, leading to a fundamental misalignment between the expected and actual memory allocation sizes. The double decoding process results in a heap-based buffer overflow condition where the application attempts to write data beyond the allocated memory boundaries. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and specifically relates to improper handling of Unicode sequences in memory management.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a significant vector for remote code execution attacks. Attackers can leverage this flaw to gain arbitrary code execution privileges on systems running vulnerable versions of BitDefender Online Anti-Virus Scanner, potentially leading to complete system compromise. The vulnerability's remote nature means that exploitation can occur without user interaction beyond visiting a malicious webpage or opening a specially crafted file, making it particularly dangerous in enterprise environments where users may encounter untrusted content. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1203, Exploitation for Client Execution, and T1059, Command and Scripting Interpreter.
The memory corruption resulting from this double decoding process creates a predictable exploitation scenario where attackers can overwrite critical memory structures, potentially leading to privilege escalation or system instability. The heap-based nature of the overflow means that the vulnerability can be particularly challenging to detect and exploit reliably, as heap corruption may not immediately cause system crashes but can lead to more subtle and persistent security issues. Organizations running vulnerable versions of BitDefender Online Anti-Virus Scanner should implement immediate mitigations including disabling ActiveX controls in web browsers, updating to patched versions, or implementing network-level protections to prevent exploitation attempts. The vulnerability highlights the importance of proper input validation and memory management in ActiveX controls, emphasizing that legacy security solutions can contain dangerous flaws that require continuous monitoring and patching to maintain effective security postures.