CVE-2009-3522 in Antivirus Professional
Summary
by MITRE
Stack-based buffer overflow in aswMon2.sys in avast! Home and Professional for Windows 4.8.1351, and possibly other versions before 4.8.1356, allows local users to cause a denial of service (system crash) and possibly gain privileges via a crafted IOCTL request to IOCTL 0xb2c80018.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 09/23/2025
The vulnerability identified as CVE-2009-3522 represents a critical stack-based buffer overflow flaw within the aswMon2.sys kernel driver component of avast! Home and Professional security software versions prior to 4.8.1356. This issue resides in the device driver's handling of IOCTL (Input/Output Control) requests, specifically targeting the IOCTL code 0xb2c80018 which is used for communication between user-mode applications and the kernel-mode driver. The flaw stems from inadequate input validation and bounds checking within the driver's processing routine, creating an exploitable condition where malicious input data can overwrite adjacent memory on the stack.
The technical implementation of this vulnerability involves the driver's failure to properly validate the size and content of data structures passed in the IOCTL request parameters. When a local user crafts a specially formatted IOCTL request with excessive data payload, the driver's processing function fails to enforce proper buffer boundaries, allowing the overflow to occur. This stack corruption can result in unpredictable behavior including system crashes, kernel panics, or in more severe cases, privilege escalation to kernel mode. The vulnerability is particularly concerning because it operates within the kernel context, meaning successful exploitation could potentially grant attackers full system control.
From an operational perspective, this vulnerability presents a significant risk to systems running affected avast products including both Home and Professional editions, indicating the flaw was present in the core monitoring driver component. The specific IOCTL code 0xb2c80018 suggests this may be part of a broader set of driver interfaces that could be similarly affected, though the primary concern centers on this particular request handler.
Mitigation strategies for CVE-2009-3522 should prioritize immediate patching of affected avast! software versions to 4.8.1356 or later, which contains the necessary driver updates to address the buffer overflow condition. System administrators should also implement monitoring for unusual IOCTL activity patterns that might indicate exploitation attempts, though detection may be challenging given the kernel-level nature of the vulnerability. The remediation aligns with common cybersecurity practices for kernel-mode vulnerabilities and follows the principle of least privilege by ensuring that only legitimate driver interfaces are accessible. Organizations should also consider implementing additional security controls such as driver signature enforcement and kernel-mode exploit detection systems to provide defense-in-depth against similar vulnerabilities. This issue demonstrates the critical importance of proper input validation in kernel drivers and aligns with CWE-121 stack-based buffer overflow categories that are frequently targeted in privilege escalation attacks. The vulnerability's classification under ATT&CK technique T1068 for privilege escalation through kernel exploits underscores the severity and potential impact of such flaws in security software components.