CVE-2007-2830 in MadWifi
Summary
by MITRE
The ath_beacon_config function in if_ath.c in MadWifi before 0.9.3.1 allows remote attackers to cause a denial of service (system crash) via crafted beacon interval information when scanning for access points, which triggers a divide-by-zero error.
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Analysis
by VulDB Data Team • 07/20/2019
The vulnerability identified as CVE-2007-2830 represents a critical denial of service flaw within the MadWifi wireless driver implementation. This issue affects versions prior to 0.9.3.1 and specifically targets the ath_beacon_config function located in the if_ath.c source file. The flaw manifests when remote attackers exploit crafted beacon interval information during wireless network scanning operations, creating a condition that results in system crashes and complete service disruption. The vulnerability operates at the kernel level within the wireless networking stack, making it particularly dangerous as it can be triggered without requiring local access or authentication.
The technical root cause of this vulnerability stems from inadequate input validation within the beacon configuration processing logic. When the ath_beacon_config function receives malformed beacon interval data, it fails to properly validate the incoming parameters before performing arithmetic operations. This deficiency leads to a divide-by-zero error condition that causes the kernel to crash and subsequently reboot the affected system. The vulnerability is classified as a divide-by-zero error, which aligns with CWE-369, a well-known weakness category that encompasses improper handling of division operations that result in zero denominators. The flaw demonstrates poor defensive programming practices where the system does not adequately sanitize input data before processing, creating an exploitable condition that can be remotely triggered through wireless network scanning activities.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential system reliability issues and denial of service attacks against wireless infrastructure. Attackers can leverage this weakness to repeatedly crash wireless access points, wireless routers, or client devices that utilize the affected MadWifi driver, effectively rendering wireless networking services unavailable to legitimate users. This makes the vulnerability particularly dangerous in environments where wireless connectivity is critical for business operations or security monitoring. The remote exploitation capability means that attackers do not need physical access to the target systems, allowing them to conduct attacks from network distances. From an attack chain perspective, this vulnerability aligns with ATT&CK technique T1499.002, which covers network denial of service attacks, and represents a classic example of how kernel-level flaws can be exploited to create system-wide disruptions.
Mitigation strategies for this vulnerability primarily involve immediate software updates to versions 0.9.3.1 and later, which contain the necessary patches to address the divide-by-zero condition in beacon interval processing. System administrators should prioritize patching affected wireless infrastructure components, including access points, routers, and client devices that utilize the MadWifi driver. Additionally, network monitoring should be enhanced to detect unusual beacon interval patterns that might indicate exploitation attempts, though this represents a reactive measure rather than a preventive solution. The vulnerability highlights the importance of input validation and proper error handling in kernel modules, emphasizing the need for robust defensive programming practices. Organizations should also implement network segmentation strategies to limit the impact of potential exploitation and maintain comprehensive system monitoring to detect and respond to service disruptions promptly.