CVE-2005-0403 in Red Hat
Summary
by MITRE
init_dev in tty_io.c in the Red Hat backport of NPTL to Red Hat Enterprise Linux 3 does not properly clear controlling tty s in multi-threaded applications, which allows local users to cause a denial of service (crash) and possibly gain tty access via unknown attack vectors that trigger an access of a pointer to a freed structure.
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Analysis
by VulDB Data Team • 06/01/2019
The vulnerability described in CVE-2005-0403 represents a critical flaw in the Linux kernel's handling of terminal devices within multi-threaded applications. This issue specifically affects the Red Hat backport of the Native POSIX Thread Library (NPTL) implementation on Red Hat Enterprise Linux 3 systems. The problem manifests in the init_dev function located within the tty_io.c source file, which is responsible for initializing terminal device structures. When multi-threaded applications execute, the improper clearing of controlling terminal information creates a dangerous state where terminal resources become improperly managed. This flaw essentially allows the kernel to maintain references to terminal structures that have already been freed, creating a scenario where memory corruption can occur during subsequent operations.
The technical exploitation of this vulnerability occurs through the improper management of terminal device pointers during thread execution. When threads within an application terminate or when terminal control is transferred between threads, the init_dev function fails to properly clear the controlling terminal reference. This results in a dangling pointer situation where a pointer continues to reference memory that has been deallocated. The vulnerability is particularly dangerous because it can be triggered by various attack vectors that cause the system to access this freed structure pointer, leading to unpredictable behavior. The flaw can result in kernel crashes due to memory access violations, but more concerning is the potential for local privilege escalation that could allow attackers to gain unauthorized access to terminal devices. This issue directly relates to CWE-415 which describes "Double Free" vulnerabilities and CWE-416 which addresses "Use After Free" conditions in memory management.
The operational impact of CVE-2005-0403 extends beyond simple denial of service scenarios to potentially compromise system security and stability. Local users who can execute multi-threaded applications on affected systems can trigger the vulnerability through various means, including running specific applications or manipulating thread execution patterns. The crash conditions can disrupt system services and potentially provide attackers with opportunities to escalate privileges by gaining access to terminal devices that should be restricted. This vulnerability particularly affects server environments where multi-threaded applications are common, as it can be exploited to destabilize critical system processes. The issue is compounded by the fact that the attack vectors are not well-defined, making it difficult for system administrators to predict or prevent exploitation. According to ATT&CK framework, this vulnerability aligns with T1068 which covers "Exploitation for Privilege Escalation" and T1499 which addresses "Endpoint Denial of Service" techniques.
Mitigation strategies for CVE-2005-0403 require immediate system updates and careful monitoring of affected environments. The most effective approach involves applying the official Red Hat security patches that address the improper memory management in the tty_io.c file. System administrators should prioritize updating all Red Hat Enterprise Linux 3 systems to ensure the patched version of the NPTL implementation is installed. Additionally, implementing process monitoring to detect unusual thread behavior and terminal access patterns can help identify potential exploitation attempts. Organizations should also consider restricting the execution of multi-threaded applications on critical systems until patches are applied. The vulnerability highlights the importance of proper memory management in kernel-level code and underscores the need for thorough testing of threading implementations in operating system components. Regular vulnerability assessments and security audits should be conducted to identify similar memory management issues that could present similar risks. System hardening measures including kernel parameter tuning and access control restrictions can provide additional layers of protection against exploitation attempts.