CVE-2007-2845 in Avast
Summary
by MITRE
Heap-based buffer overflow in the CAB unpacker in avast! Anti-Virus Managed Client before 4.7.700 allows user-assisted remote attackers to execute arbitrary code via a crafted CAB archive, resulting from an "integer cast around".
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Analysis
by VulDB Data Team • 07/20/2019
The vulnerability described in CVE-2007-2845 represents a critical heap-based buffer overflow affecting the CAB unpacker component within avast! Anti-Virus Managed Client versions prior to 4.7.700. This flaw resides in the handling of compressed archive files and demonstrates a classic integer overflow condition that can be exploited to manipulate memory allocation and execution flow. The vulnerability specifically manifests when processing crafted CAB archives, making it particularly dangerous in environments where users might encounter maliciously constructed archive files through various attack vectors.
The technical root cause of this vulnerability stems from an "integer cast around" condition within the CAB unpacking routine, which falls under the CWE-190 category of Integer Overflow or Wraparound. This condition occurs when a program performs arithmetic operations on integer values that exceed their maximum representable value, causing the integer to wrap around to a much smaller value. In the context of buffer allocation, this wraparound results in insufficient memory being allocated for the decompressed data, creating a heap-based buffer overflow scenario where subsequent data writes can overwrite adjacent memory regions. The vulnerability is classified under the ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution, as it enables arbitrary code execution through compromised client systems.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the capability to fully compromise the affected system through user-assisted remote exploitation. Attackers can craft malicious CAB archives that, when processed by the vulnerable avast Managed Client, making it a prime target for attackers seeking to exploit widely deployed security software.
Mitigation strategies for CVE-2007-2845 should prioritize immediate patching of affected avast! Anti-Virus Managed Client installations to version 4.7.700 or later, which contains the necessary fixes for the integer overflow condition. Organizations should also implement network-level controls to restrict access to potentially malicious archive files and employ additional security measures such as sandboxing for archive processing. The vulnerability highlights the importance of proper input validation and integer overflow prevention techniques in security software, particularly in components that handle untrusted data from external sources. System administrators should also consider implementing monitoring for unusual file processing activities and maintain up-to-date threat intelligence to detect potential exploitation attempts targeting this specific vulnerability.