CVE-2005-0179 in Linux
Summary
by MITRE
Linux kernel 2.4.x and 2.6.x allows local users to cause a denial of service (CPU and memory consumption) and bypass RLIM_MEMLOCK limits via the mlockall call.
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Analysis
by VulDB Data Team • 03/10/2021
The vulnerability described in CVE-2005-0179 represents a critical security flaw within the Linux kernel version 2.4.x and 2.6.x series that affects system resource management and privilege escalation mechanisms. This issue specifically targets the memory locking functionality implemented through the mlockall system call, which is designed to prevent memory pages from being swapped to disk. The flaw enables local attackers to exploit the kernel's handling of memory locking operations, creating a scenario where system resources can be consumed excessively while simultaneously bypassing established security limits that should restrict memory locking capabilities.
The technical implementation of this vulnerability stems from improper validation and handling of the mlockall system call within kernel memory management subsystems. When a local user executes mlockall with specific parameters, the kernel fails to properly enforce resource limits and memory constraints that are typically enforced through the RLIM_MEMLOCK resource limit. This allows the malicious process to lock an excessive amount of virtual memory into physical RAM, leading to resource exhaustion that can cause system instability and denial of service conditions. The flaw operates at the kernel level and leverages the inherent design of memory management controls to create a bypass mechanism that circumvents the intended security boundaries.
From an operational impact perspective, this vulnerability presents significant risks to system availability and stability. Local attackers can consume excessive CPU cycles and memory resources through repeated mlockall calls, potentially causing system-wide performance degradation or complete system hangs. The ability to bypass RLIM_MEMLOCK limits means that malicious processes can circumvent the normal memory locking restrictions that are typically used to prevent denial of service attacks and ensure fair resource allocation among processes. This vulnerability is particularly dangerous because it allows local users to escalate their impact beyond what would normally be possible through standard privilege boundaries, creating a vector for both resource exhaustion attacks and potential privilege escalation.
The vulnerability aligns with several cybersecurity frameworks and threat models, including the Common Weakness Enumeration CWE-248, which categorizes this as an "Uncaught Exception" or improper handling of system calls that leads to resource exhaustion. From the MITRE ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and resource consumption, specifically covering T1068 for bypassing security restrictions and T1499 for resource exhaustion attacks. The flaw also demonstrates characteristics of T1055 for kernel-level exploitation and T1566 for creating malicious system conditions that can be exploited for further attacks. Organizations should recognize that this vulnerability represents a fundamental breakdown in kernel memory management controls that can be exploited by any local user with access to the system, making it particularly concerning for multi-user environments and server deployments where local access might be more readily available.
Mitigation strategies for CVE-2005-0179 should focus on kernel updates and system hardening measures that address the root cause of the memory locking bypass. System administrators should immediately apply the appropriate kernel patches that fix the mlockall implementation and ensure proper enforcement of RLIM_MEMLOCK limits. Additionally, implementing proper monitoring and alerting for unusual memory locking patterns can help detect exploitation attempts. Resource management configurations should be reviewed to ensure that appropriate limits are set for memory locking operations, and access controls should be enforced to minimize the potential for local privilege escalation. Organizations should also consider implementing process monitoring tools that can detect and prevent excessive memory locking operations, while maintaining regular kernel security updates to prevent similar vulnerabilities from being introduced in future versions.