CVE-2007-2831 in MadWifi
Summary
by MITRE
Array index error in the (1) ieee80211_ioctl_getwmmparams and (2) ieee80211_ioctl_setwmmparams functions in net80211/ieee80211_wireless.c in MadWifi before 0.9.3.1 allows local users to cause a denial of service (system crash), possibly obtain kernel memory contents, and possibly execute arbitrary code via a large negative array index value.
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Analysis
by VulDB Data Team • 07/20/2021
The vulnerability described in CVE-2007-2831 represents a critical array index error within the MadWifi wireless networking driver implementation. This flaw exists in the ieee80211_ioctl_getwmmparams and ieee80211_ioctl_setwmmparams functions located in the net80211/ieee80211_wireless.c source file. The vulnerability affects MadWifi versions prior to 0.9.3.1 and demonstrates a classic buffer over-read condition that can be exploited by local attackers with kernel-level privileges. The flaw stems from improper validation of array index values passed through wireless network management ioctls, specifically when handling WMM (Wireless MultiMedia) parameters.
The technical implementation of this vulnerability involves the manipulation of array indexing operations within kernel space wireless driver code. When maliciously crafted ioctl commands are issued with large negative array index values, the ieee80211_ioctl_getwmmparams and ieee80211_ioctl_setwmmparams functions fail to properly validate input parameters before using them as array indices. This validation failure creates an exploitable condition where the kernel attempts to access memory locations far outside the intended array boundaries. The vulnerability is classified as a CWE-129: Improper Validation of Array Index, which directly maps to the fundamental flaw in input validation mechanisms. The improper bounds checking allows attackers to bypass normal memory access restrictions and potentially traverse into kernel memory space.
The operational impact of this vulnerability extends beyond simple denial of service to include potential information disclosure and arbitrary code execution capabilities. Local users with access to the wireless networking interface can trigger system crashes through kernel memory corruption, effectively causing a denial of service condition. More critically, the vulnerability may enable attackers to read kernel memory contents, potentially exposing sensitive data such as cryptographic keys, network credentials, or other confidential information stored in kernel memory. The arbitrary code execution capability represents the most severe aspect of this vulnerability, as it allows attackers to escalate privileges and potentially take complete control of the affected system. This vulnerability directly aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation and T1059.001: Command and Scripting Interpreter - PowerShell, where local privilege escalation leads to system compromise.
Mitigation strategies for this vulnerability require immediate patching of affected MadWifi installations to version 0.9.3.1 or later, which contains the necessary input validation fixes. System administrators should also implement proper access controls to limit local user privileges and restrict access to wireless management interfaces. Network segmentation and monitoring solutions should be deployed to detect anomalous ioctl activity patterns that might indicate exploitation attempts. The vulnerability highlights the importance of input validation in kernel space code and demonstrates how seemingly minor flaws in parameter checking can result in severe security implications. Organizations should also consider implementing kernel module signing policies and runtime protection mechanisms to prevent exploitation of similar vulnerabilities in other kernel components. Regular security audits of kernel space code and adherence to secure coding practices are essential to prevent recurrence of such array index validation errors.