CVE-2017-7506 in SPICE
Summary
by MITRE
spice versions though 0.13 are vulnerable to out-of-bounds memory access when processing specially crafted messages from authenticated attacker to the spice server resulting into crash and/or server memory leak.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-7506 affects the spice virtualization protocol implementation across versions through 0.13, representing a critical security flaw that can be exploited by authenticated attackers to compromise system stability and memory integrity. This vulnerability resides within the spice server component that handles communication between virtualization clients and servers, making it particularly dangerous in enterprise virtualization environments where multiple authenticated users may interact with the system. The flaw manifests when the server processes specially crafted malicious messages that trigger improper memory handling during message parsing operations, creating a pathway for unauthorized system disruption.
The technical root cause of this vulnerability stems from insufficient bounds checking within the spice server's message processing routines, specifically in how it handles incoming data structures from authenticated clients. When the server receives malformed or crafted messages containing oversized data fields or improperly structured parameters, the parsing logic fails to validate the message boundaries before attempting memory allocation or data copying operations. This lack of proper input validation creates an out-of-bounds memory access condition that can result in memory corruption, program termination, or unintended memory leakage patterns. The vulnerability aligns with CWE-129, which specifically addresses insufficient validation of length of input buffers, and represents a classic example of buffer over-read conditions that can be exploited through crafted inputs.
The operational impact of CVE-2017-7506 extends beyond simple service disruption to potentially enable more sophisticated attack vectors within virtualized environments. An authenticated attacker who can establish a connection to the spice server can leverage this vulnerability to cause denial of service conditions through server crashes, leading to temporary unavailability of virtual desktop services. Additionally, the memory leak aspect of this vulnerability can gradually consume server resources over time, potentially leading to system instability or performance degradation that may not be immediately apparent. In enterprise settings where spice servers handle multiple concurrent connections from virtual desktop users, this vulnerability could be exploited to create cumulative resource exhaustion that affects overall system performance. The attack requires only authenticated access, making it particularly concerning for environments where access controls may not be sufficiently restrictive.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1499.004 for network denial of service and T1059 for command and control through compromised virtualization protocols. The vulnerability can be exploited as part of a broader attack chain where an initial foothold through legitimate authentication leads to service disruption and potential information gathering. Mitigation strategies should focus on immediate patching of affected spice server implementations to version 0.13 or later, which includes proper bounds checking and input validation mechanisms. Network segmentation and access control measures should be implemented to limit who can establish connections to spice servers, while monitoring should be deployed to detect unusual patterns of connection attempts or service disruptions that might indicate exploitation attempts. Regular security assessments of virtualization infrastructure and implementation of principle of least privilege access controls will help reduce the attack surface and prevent unauthorized exploitation of this vulnerability.