CVE-2013-4537 in QEMU
Summary
by MITRE
The ssi_sd_transfer function in hw/sd/ssi-sd.c in QEMU before 1.7.2 allows remote attackers to execute arbitrary code via a crafted arglen value in a savevm image.
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Analysis
by VulDB Data Team • 06/20/2021
The vulnerability identified as CVE-2013-4537 resides within the QEMU virtualization platform's handling of savevm images, specifically in the ssi_sd_transfer function located in hw/sd/ssi-sd.c. This flaw represents a critical security issue that affects QEMU versions prior to 1.7.2, potentially allowing remote attackers to execute arbitrary code on systems running vulnerable virtual machines. The vulnerability stems from insufficient input validation within the savevm image processing mechanism, where the arglen parameter is not properly sanitized or checked before being used in memory operations.
The technical implementation of this vulnerability exploits a buffer over-read condition that occurs when the ssi_sd_transfer function processes savevm images containing maliciously crafted arglen values. This flaw falls under the category of improper input validation and memory safety issues, which are commonly classified as CWE-129 and CWE-787 within the Common Weakness Enumeration framework. The function fails to validate the length parameter against expected boundaries, allowing attackers to manipulate the arglen value to cause memory access violations that can be leveraged for code execution. When QEMU attempts to process these malformed savevm images, the improper handling of the arglen parameter leads to unpredictable memory access patterns that can be exploited to overwrite critical memory locations or execute arbitrary instructions.
The operational impact of this vulnerability extends beyond simple code execution, as it can be leveraged to compromise entire virtualized environments. Remote attackers who can influence the savevm image content or gain access to savevm files can exploit this vulnerability to execute arbitrary code with the privileges of the QEMU process. This represents a significant threat to virtualization security, as it allows attackers to potentially escape virtual machine boundaries and gain access to underlying host resources. The vulnerability is particularly dangerous in cloud computing environments where multiple virtual machines share the same physical host, as successful exploitation could lead to lateral movement and privilege escalation across the virtualized infrastructure. Additionally, since savevm images are often used for backup, migration, and state persistence operations, the attack surface is broadened to include any system that processes these images.
Mitigation strategies for CVE-2013-4537 primarily focus on upgrading to QEMU version 1.7.2 or later, which contains the necessary patches to address the improper input validation in the ssi_sd_transfer function. Organizations should also implement strict access controls and validation of savevm images, particularly those received from untrusted sources. The implementation of input sanitization measures and bounds checking within the savevm processing pipeline provides additional defense-in-depth layers. Security practitioners should consider implementing network segmentation and monitoring for suspicious savevm image processing activities. This vulnerability aligns with ATT&CK technique T1059.001 for command and script injection, and T1078.004 for valid accounts, as exploitation may involve leveraging legitimate system accounts and processes to execute malicious code within the virtualized environment. The patch for this vulnerability specifically addresses the buffer over-read condition and implements proper validation of the arglen parameter to prevent malicious manipulation of memory access patterns.