CVE-2017-6210 in virglrenderer
Summary
by MITRE
The vrend_decode_reset function in vrend_decode.c in virglrenderer before 0.6.0 allows local guest OS users to cause a denial of service (NULL pointer dereference and QEMU process crash) by destroying context 0 (zero).
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Analysis
by VulDB Data Team • 09/08/2020
The vulnerability described in CVE-2017-6210 affects the virglrenderer library version 0.6.0 and earlier, specifically within the vrend_decode_reset function located in vrend_decode.c. This issue represents a critical denial of service vulnerability that can be exploited by local guest operating system users to crash the QEMU process and cause system instability. The vulnerability is particularly concerning in virtualized environments where guest operating systems may have elevated privileges or where malicious actors could potentially leverage this weakness to disrupt virtual machine operations.
The technical flaw stems from inadequate input validation within the vrend_decode_reset function, which fails to properly handle the destruction of context zero. When a local guest OS user attempts to destroy context 0, the function executes a NULL pointer dereference operation that ultimately leads to a segmentation fault and subsequent QEMU process crash. This behavior aligns with CWE-476, which categorizes NULL pointer dereference as a common vulnerability pattern that can lead to system instability and denial of service conditions. The vulnerability demonstrates a classic lack of proper error handling and resource management within the graphics virtualization layer.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the stability of entire virtualized environments. In cloud computing and enterprise virtualization deployments, such a vulnerability could enable attackers to repeatedly crash virtual machines, causing significant operational disruptions and potentially leading to data loss or service unavailability. The fact that this vulnerability affects the QEMU process means that any virtual machine running on a compromised host could be at risk, making this a particularly dangerous issue in multi-tenant cloud environments. Attackers could exploit this vulnerability to systematically destabilize virtualized infrastructure, potentially causing cascading failures that affect multiple guest operating systems.
Mitigation strategies for this vulnerability should focus on immediate patching of the virglrenderer library to version 0.6.0 or later, which contains the necessary fixes to prevent the NULL pointer dereference. Organizations should also implement monitoring solutions to detect unusual patterns of context destruction that might indicate exploitation attempts. Network segmentation and privilege separation can help limit the impact of potential exploitation, while regular security assessments of virtualization components should be conducted to identify similar vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under the T1499 sub-technique for Network Denial of Service, highlighting the importance of securing virtualization infrastructure components. Additionally, implementing proper input validation and error handling mechanisms within graphics virtualization layers can prevent similar issues from occurring in other components of the system.