CVE-2011-1006 in libcgroup
Summary
by MITRE
Heap-based buffer overflow in the parse_cgroup_spec function in tools/tools-common.c in the Control Group Configuration Library (aka libcgroup or libcg) before 0.37.1 allows local users to gain privileges via a crafted controller list on the command line of an application. NOTE: it is not clear whether this issue crosses privilege boundaries.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/21/2021
The vulnerability identified as CVE-2011-1006 represents a critical heap-based buffer overflow within the Control Group Configuration Library, commonly known as libcgroup or libcg. This library serves as a fundamental component for managing Linux control groups, which are essential for resource accounting and isolation in modern Linux systems. The flaw exists specifically within the parse_cgroup_spec function located in tools/tools-common.c, making it a core element of the system's configuration parsing mechanism. Control groups are crucial for system administrators to enforce resource limits, monitor usage, and manage process isolation, particularly in virtualized environments and containerized applications.
The technical implementation of this vulnerability stems from inadequate input validation within the parse_cgroup_spec function, which processes controller lists provided through command line arguments. When applications utilizing libcgroup parse command line parameters containing specially crafted controller specifications, the function fails to properly bounds-check heap-allocated memory regions. This oversight creates a condition where an attacker can overflow the allocated buffer and potentially overwrite adjacent memory locations, including critical control data structures or function pointers. The heap-based nature of the overflow means that memory corruption occurs in the heap segment rather than the stack, making exploitation more complex but still potentially devastating. This vulnerability falls under CWE-121, heap-based buffer overflow, and represents a classic example of improper input validation leading to memory corruption.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it could potentially enable attackers to execute arbitrary code with elevated privileges. In systems where applications rely on libcgroup for control group management, particularly those running with elevated permissions, a local attacker could craft malicious command line arguments to trigger the buffer overflow. The privilege boundary crossing aspect noted in the CVE description suggests that while the initial exploit might start from a local user context, it could potentially be leveraged to escalate privileges to root or other system-level accounts. This type of vulnerability aligns with ATT&CK technique T1068, 'Local Privilege Escalation', and represents a significant concern for system administrators managing Linux environments, especially those deploying container orchestration platforms or cloud infrastructure where control groups are extensively used.
The mitigation strategy for CVE-2011-1006 primarily involves upgrading to libcgroup version 0.37.1 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should prioritize this update across all systems utilizing libcgroup functionality, particularly in environments where applications might be exposed to untrusted command line inputs. Additional defensive measures include implementing strict input validation for command line parameters, employing sandboxing techniques for applications that process control group specifications, and monitoring for suspicious command line patterns that might indicate exploitation attempts. Organizations should also consider implementing privilege separation mechanisms to limit the impact of potential exploitation, ensuring that applications using libcgroup do not run with unnecessary elevated privileges. Regular security audits of control group configurations and monitoring of system logs for anomalous behavior can help detect potential exploitation attempts and provide early warning of compromise.