CVE-2013-4530 in QEMU
Summary
by MITRE
Buffer overflow in hw/ssi/pl022.c in QEMU before 1.7.2 allows remote attackers to cause a denial of service or possibly execute arbitrary code via crafted tx_fifo_head and rx_fifo_head values in a savevm image.
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Analysis
by VulDB Data Team • 06/20/2021
The vulnerability identified as CVE-2013-4530 represents a critical buffer overflow flaw within the QEMU emulator's PL022 serial peripheral emulation component. This issue exists in the hw/ssi/pl022.c file and affects QEMU versions prior to 1.7.2, creating a significant security risk for virtualized environments that rely on this emulation layer. The flaw manifests when processing savevm images that contain crafted tx_fifo_head and rx_fifo_head values, which are used to manage transmit and receive FIFO (First In, First Out) buffers in the serial communication hardware emulation.
The technical nature of this vulnerability stems from insufficient validation of input parameters within the savevm state restoration process. When QEMU attempts to restore the state of a virtual machine that includes a PL022 serial peripheral, it reads the FIFO head pointers from the savevm image without proper bounds checking. These pointers control the positioning within the FIFO buffers, and when maliciously crafted values exceed the allocated buffer boundaries, they trigger a buffer overflow condition. This overflow can overwrite adjacent memory locations, potentially corrupting critical data structures or executing arbitrary code through memory corruption techniques.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution within the host system. Attackers who can influence the savevm image content can craft malicious values that cause the buffer overflow to overwrite function pointers, return addresses, or other critical program state information. This makes the vulnerability particularly dangerous in environments where QEMU instances are exposed to untrusted input or where virtual machine snapshots are shared between parties. The vulnerability affects virtualization platforms that utilize QEMU's PL022 emulation for serial communication, which is common in embedded system emulation, network device simulation, and various virtualized infrastructure deployments.
Mitigation strategies for CVE-2013-4530 primarily involve upgrading to QEMU version 1.7.2 or later, which includes proper input validation and bounds checking for the FIFO head pointer values. Additionally, system administrators should implement strict access controls on savevm image files and ensure that only trusted sources can provide virtual machine state data. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and may map to ATT&CK technique T1059.007 for remote code execution through emulation layer manipulation. Organizations should also consider implementing memory protection mechanisms such as stack canaries and address space layout randomization to reduce the exploitability of similar buffer overflow conditions in their virtualization environments.