CVE-2013-2194 in Xen Elf Parser
Summary
by MITRE
Multiple integer overflows in the Elf parser (libelf) in Xen 4.2.x and earlier allow local guest administrators with certain permissions to have an unspecified impact via a crafted kernel.
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Analysis
by VulDB Data Team • 05/17/2021
The vulnerability identified as CVE-2013-2194 represents a critical security flaw within the Xen hypervisor's ELF parser component, specifically affecting versions 4.2.x and earlier. This issue resides in the libelf library implementation that Xen uses to parse executable files, creating a potential vector for privilege escalation and system compromise. The vulnerability stems from inadequate input validation within the ELF parsing routines that handle kernel modules and executables loaded by guest operating systems.
The technical flaw manifests as integer overflows occurring during the parsing of ELF headers and section structures. When a malicious guest administrator crafts a specially formatted kernel module or executable file, the libelf parser fails to properly validate integer values during memory allocation calculations. This leads to scenarios where integer arithmetic results in values that exceed the maximum representable range, causing unexpected behavior in memory management operations. The overflow conditions can occur in various parsing contexts including section header parsing, program header processing, and dynamic linking table handling within the ELF format.
From an operational perspective, this vulnerability enables local guest administrators with sufficient permissions to potentially execute arbitrary code with elevated privileges or cause denial of service conditions within the hypervisor environment. The unspecified impact suggests that depending on the specific overflow conditions and system configuration, attackers could achieve privilege escalation to root-level access, corrupt memory structures, or disrupt normal hypervisor operations. This represents a significant threat to cloud computing environments and virtualized infrastructure where guest administrators might be granted elevated privileges for legitimate system management tasks.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic produces results that exceed the maximum value that can be represented by the data type. This flaw also maps to ATT&CK technique T1068, Exploitation for Privilege Escalation, as it allows local users to escalate their privileges within the virtualized environment. Organizations using Xen hypervisors should prioritize immediate patching of affected versions, as the vulnerability can be exploited by users with guest administrative privileges to compromise the entire virtualization infrastructure.
Mitigation strategies include upgrading to Xen version 4.3.0 or later where the integer overflow issues have been resolved through proper input validation and bounds checking. System administrators should implement strict access controls to limit guest administrator permissions and monitor for suspicious ELF file loading activities. Additionally, deploying hypervisor-level security controls such as Intel VT-d or AMD-Vi for device assignment and memory isolation can help contain potential exploitation attempts. Regular security audits of virtualized environments and monitoring for anomalous behavior in kernel module loading processes remain essential defensive measures against this class of vulnerability.