CVE-2009-2911 in SystemTap
Summary
by MITRE
SystemTap 1.0, when the --unprivileged option is used, does not properly restrict certain data sizes, which allows local users to (1) cause a denial of service or gain privileges via a print operation with a large number of arguments that trigger a kernel stack overflow, (2) cause a denial of service via crafted DWARF expressions that trigger a kernel stack frame overflow, or (3) cause a denial of service (infinite loop) via vectors that trigger creation of large unwind tables, related to Common Information Entry (CIE) and Call Frame Instruction (CFI) records.
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Analysis
by VulDB Data Team • 03/27/2025
SystemTap 1.0 presents a critical vulnerability when operating with the --unprivileged option that stems from inadequate data size restrictions within its kernel instrumentation framework. This flaw manifests in multiple attack vectors that can compromise system stability and potentially escalate privileges. The vulnerability operates through the manipulation of kernel stack operations and unwind table generation mechanisms that are fundamental to system debugging and profiling capabilities.
The technical implementation of this vulnerability exploits the insufficient validation of data parameters during kernel-level operations. When the --unprivileged option is enabled, SystemTap fails to enforce proper bounds checking on argument counts during print operations, allowing malicious users to craft inputs that trigger kernel stack overflow conditions. This occurs because the kernel's stack management does not adequately protect against excessive argument consumption that can exceed allocated stack space. The vulnerability also affects DWARF expression processing where crafted inputs can cause kernel stack frame overflows during debugging information parsing. Additionally, the system becomes susceptible to infinite loop conditions when processing unwind table generation for CIE and CFI records, creating resource exhaustion scenarios that result in denial of service.
From an operational perspective, this vulnerability represents a significant risk to systems that rely on SystemTap for performance monitoring and debugging operations. Local attackers with minimal privileges can exploit these conditions to either disrupt system services through denial of service or potentially escalate their privileges through kernel stack overflow exploitation. The impact extends beyond simple service disruption as the infinite loop conditions can exhaust system resources and potentially lead to system instability. The vulnerability affects systems where unprivileged users have access to SystemTap functionality, making it particularly concerning in multi-user environments or containerized deployments where privilege separation is critical.
The vulnerability aligns with CWE-122 (Heap-based Buffer Overflow) and CWE-20 (Improper Input Validation) categories, while also mapping to ATT&CK techniques involving privilege escalation and denial of service. The attack surface is particularly concerning because it leverages legitimate system debugging capabilities to create malicious conditions. The kernel stack overflow conditions specifically relate to improper stack management and lack of input sanitization during kernel operations. Organizations should prioritize patching systems running SystemTap 1.0 with the --unprivileged option, implementing strict access controls to limit who can invoke SystemTap functionality, and monitoring for unusual stack usage patterns or system resource consumption that might indicate exploitation attempts.
Mitigation strategies should include immediate patching of affected SystemTap versions, implementing comprehensive access controls that restrict SystemTap usage to trusted administrative users only, and deploying monitoring solutions that can detect anomalous stack overflow conditions. System administrators should also consider disabling the --unprivileged option unless absolutely required, as this significantly reduces the attack surface. The vulnerability demonstrates the importance of proper input validation and resource management in kernel-level operations, particularly when implementing debugging and profiling tools that operate with elevated privileges. Organizations should conduct thorough vulnerability assessments to identify all systems running affected SystemTap versions and ensure proper security controls are in place to prevent exploitation.