CVE-2012-0031 in HTTP Server
Summary
by MITRE
scoreboard.c in the Apache HTTP Server 2.2.21 and earlier might allow local users to cause a denial of service (daemon crash during shutdown) or possibly have unspecified other impact by modifying a certain type field within a scoreboard shared memory segment, leading to an invalid call to the free function.
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Analysis
by VulDB Data Team • 09/10/2024
The vulnerability identified as CVE-2012-0031 affects the Apache HTTP Server version 2.2.21 and earlier, specifically within the scoreboard.c component that manages shared memory segments used for process coordination. This issue represents a classic memory corruption vulnerability that arises from improper handling of data structures within shared memory regions. The flaw occurs when local users manipulate a specific type field within the scoreboard shared memory segment, which subsequently triggers an invalid memory deallocation operation during the server shutdown process. The vulnerability is particularly concerning because it can lead to daemon crashes and potential system instability, making it a significant threat to service availability.
The technical root cause of this vulnerability lies in the improper validation of memory segment data during the server shutdown sequence. When the scoreboard component processes a modified type field within the shared memory segment, it fails to properly validate the integrity of this field before attempting memory deallocation operations. This type of error falls under the CWE-125 vulnerability category, which encompasses out-of-bounds reads and memory corruption issues. The flaw demonstrates poor input validation practices where the system assumes the integrity of shared memory data without proper verification mechanisms, creating a path for malicious manipulation that can result in arbitrary code execution or system crashes. The vulnerability is classified as a local privilege escalation issue since it requires local access but can cause remote denial of service effects through system instability.
From an operational impact perspective, this vulnerability poses significant risks to Apache HTTP Server deployments, particularly in environments where multiple processes share memory segments for coordination. During normal server operation, the scoreboard component maintains information about worker processes and their states, but when a malicious local user modifies the type field in the shared memory segment, it can cause the server to make invalid calls to the free function. This leads to potential daemon crashes during shutdown operations, effectively causing a denial of service condition that can disrupt web services for legitimate users. The impact extends beyond simple service interruption as the vulnerability may also enable unspecified other impacts that could potentially allow for privilege escalation or information disclosure depending on the specific implementation details of the affected system.
Security practitioners should implement multiple layers of mitigation to address this vulnerability effectively. The primary recommendation involves upgrading to Apache HTTP Server version 2.2.22 or later, where this vulnerability has been patched through proper input validation of shared memory segments. Additionally, system administrators should consider implementing strict access controls on shared memory segments to prevent unauthorized modification of scoreboard data. The mitigation strategy should also include monitoring for unusual memory access patterns and implementing process isolation techniques that limit the impact of potential exploitation. Organizations should follow ATT&CK framework tactics related to privilege escalation and defense evasion by ensuring proper memory management practices and implementing robust process monitoring. The vulnerability highlights the importance of proper memory management in multi-process systems and serves as a reminder of the critical need for thorough input validation in shared memory contexts. Regular security assessments and vulnerability scanning should include checks for similar memory corruption issues in other server components to prevent similar exploitation vectors from being overlooked.