CVE-2012-0875 in SystemTap
Summary
by MITRE
SystemTap 1.7, 1.6.7, and probably other versions, when unprivileged mode is enabled, allows local users to obtain sensitive information from kernel memory or cause a denial of service (kernel panic and crash) via vectors related to crafted DWARF data, which triggers a read of an invalid pointer.
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Analysis
by VulDB Data Team • 01/02/2025
CVE-2012-0875 represents a critical vulnerability in SystemTap, a dynamic instrumentation tool for Linux systems that enables runtime monitoring and debugging of kernel and user-space applications. This vulnerability specifically affects versions 1.7, 1.6.7, and potentially other releases of the SystemTap framework when operating in unprivileged mode. The flaw stems from inadequate input validation during the processing of DWARF debugging data, which is commonly used by SystemTap to collect and analyze program information. When maliciously crafted DWARF data is processed, the system fails to properly validate pointer references, leading to a scenario where invalid memory addresses are accessed during kernel operations.
The technical exploitation of this vulnerability occurs through the manipulation of DWARF debugging information that SystemTap processes when monitoring applications. In unprivileged mode, SystemTap typically operates with reduced privileges while still maintaining the ability to access kernel memory structures for instrumentation purposes. However, the vulnerability arises when the tool encounters malformed DWARF data containing invalid pointer references that should normally be rejected during parsing. The flaw manifests as a read operation on an invalid memory pointer, which can result in two distinct but serious outcomes. The first outcome involves information disclosure, where attackers can potentially extract sensitive kernel memory contents, including cryptographic keys, passwords, or other confidential data that should remain protected within kernel space. The second outcome is a denial of service condition that can trigger a kernel panic, causing the entire system to crash and requiring manual rebooting.
This vulnerability directly maps to CWE-125, which describes "Out-of-Bounds Read" conditions where a program reads memory beyond the boundaries of a valid buffer or pointer. The flaw also aligns with CWE-248, covering "Uncaught Exception" scenarios where an exception or error condition is not properly handled, leading to unexpected system behavior. From an operational perspective, the impact of CVE-2012-0875 extends beyond simple system instability as it compromises the confidentiality and integrity of kernel memory. Attackers exploiting this vulnerability could potentially gain unauthorized access to sensitive system information, undermining the fundamental security assumptions of the Linux kernel's memory protection mechanisms. The vulnerability is particularly concerning because it operates within the context of a legitimate system administration tool, making detection more challenging and potentially allowing attackers to maintain persistent access while gathering intelligence.
The exploitation of this vulnerability demonstrates techniques aligned with ATT&CK tactic T1059, specifically the use of system commands and execution flows to manipulate kernel memory access patterns. The attack vector leverages the legitimate functionality of SystemTap's debugging capabilities to achieve unauthorized memory access, representing a sophisticated approach to privilege escalation and information gathering. Organizations should implement immediate mitigations including disabling unprivileged mode in SystemTap installations, applying the latest security patches from the SystemTap project, and monitoring for anomalous DWARF data processing activities. Additionally, system administrators should consider restricting access to SystemTap to authorized users only and implementing proper input validation controls for any debugging data that might be processed through the system. The vulnerability underscores the importance of validating all external input data, particularly in kernel-level tools that have broad access to system resources, and highlights the need for comprehensive security testing of instrumentation frameworks that operate with elevated privileges or kernel access capabilities.