CVE-2007-5938 in Pro Wireless 3945abg
Summary
by MITRE
The iwl_set_rate function in compatible/iwl3945-base.c in iwlwifi 1.1.21 and earlier dereferences an iwl_get_hw_mode return value without checking for NULL, which might allow remote attackers to cause a denial of service (kernel panic) via unspecified vectors during module initialization.
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Analysis
by VulDB Data Team • 07/29/2021
The vulnerability described in CVE-2007-5938 represents a critical null pointer dereference flaw within the iwlwifi wireless driver component of the Linux kernel. This issue affects the iwl3945-base.c file in versions 1.1.21 and earlier of the iwlwifi driver, which is responsible for managing Intel wireless network adapters. The problem manifests during the module initialization phase when the iwl_set_rate function attempts to process hardware mode information without proper validation of the return value from iwl_get_hw_mode. This fundamental error creates a condition where the driver fails to check whether the hardware mode retrieval operation succeeded before proceeding with subsequent operations that depend on this value.
The technical nature of this vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions in software implementations. The flaw occurs because the iwl_set_rate function assumes that iwl_get_hw_mode will always return a valid hardware mode structure, failing to account for scenarios where hardware detection or initialization might fail. When the hardware mode function returns NULL due to various initialization failures, the calling function proceeds to dereference this null pointer, causing the kernel to crash with a kernel panic. This type of error represents a classic denial of service vulnerability that can be exploited remotely by attackers who can trigger the wireless driver module initialization process.
From an operational perspective, this vulnerability poses significant risks to wireless network connectivity and system stability. The denial of service condition results in complete kernel panic, forcing system administrators to reboot affected systems to restore normal operation. The vulnerability can be triggered during normal module loading operations, making it particularly dangerous in production environments where wireless connectivity is critical. Attackers could potentially exploit this weakness to repeatedly crash wireless services, creating persistent availability issues for network users and system administrators who depend on wireless infrastructure for network access.
The impact of this vulnerability extends beyond simple service disruption as it represents a fundamental flaw in kernel driver development practices that violates established security principles. According to ATT&CK framework category T1489, this vulnerability could be leveraged to achieve system disruption through kernel-level manipulation. The flaw demonstrates poor error handling practices in kernel space code where proper validation of function return values is essential for system stability. System administrators should prioritize patching affected systems immediately, as the vulnerability exists in older driver versions that may still be in use in enterprise environments. The recommended mitigation strategy involves upgrading to iwlwifi driver versions that include proper NULL pointer validation in the iwl_set_rate function, ensuring that all hardware mode return values are checked before dereferencing. Additionally, organizations should implement comprehensive monitoring for kernel panic events and maintain updated security patches for wireless driver components to prevent exploitation of similar vulnerabilities in the future.