CVE-2015-8843 in Foxit
Summary
by MITRE
The Foxit Cloud Update Service (FoxitCloudUpdateService) in Foxit Reader 6.1 through 6.2.x and 7.x before 7.2.2, when an update to the Cloud plugin is available, allows local users to gain privileges by writing crafted data to a shared memory region, which triggers memory corruption.
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Analysis
by VulDB Data Team • 10/06/2018
The vulnerability identified as CVE-2015-8843 represents a critical privilege escalation flaw within the Foxit Cloud Update Service component of Foxit Reader software versions 6.1 through 6.2.x and 7.x prior to 7.2.2. This issue specifically targets the shared memory region mechanism used by the Foxit Cloud Update Service to communicate between different process components. The vulnerability stems from insufficient input validation and memory management practices within the update service implementation, creating a pathway for local attackers to manipulate system resources through crafted data injection techniques. The flaw exists in the way the service handles memory operations during plugin update processes, particularly when the system detects available updates for the cloud plugin functionality.
The technical exploitation of this vulnerability occurs through a specific memory corruption vector that leverages shared memory access patterns within the Foxit Cloud Update Service. When the service identifies that an update is available for the cloud plugin, it initializes a shared memory region to facilitate data exchange between processes. Local users can exploit this by writing crafted data directly into the shared memory segment, which then triggers memory corruption conditions that can be leveraged for privilege escalation. The underlying flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflows, though in this case the corruption manifests through shared memory manipulation rather than traditional buffer overflow scenarios. The attack vector requires local system access but can potentially elevate privileges from standard user to system-level access, making it particularly dangerous in multi-user environments.
The operational impact of CVE-2015-8843 extends beyond simple privilege escalation, as it provides attackers with a persistent mechanism for system compromise within environments where Foxit Reader is deployed. This vulnerability can be exploited in various attack scenarios including targeted attacks against specific users, privilege escalation within corporate networks, and potentially as part of broader attack chains where initial access has been gained through other vectors. The shared memory corruption allows for arbitrary code execution in the context of the Foxit Cloud Update Service process, which typically runs with elevated privileges due to its role in system update management. This makes the vulnerability particularly attractive to attackers seeking to establish persistent access or escalate their privileges within a compromised system. The impact is further amplified because the Foxit Reader application is commonly deployed in enterprise environments, making this vulnerability a potential target for advanced persistent threats.
Mitigation strategies for CVE-2015-8843 should focus on immediate patching of affected Foxit Reader versions, with particular emphasis on upgrading to Foxit Reader 7.2.2 or later where the vulnerability has been addressed through improved memory management and input validation. System administrators should implement process monitoring to detect unusual shared memory access patterns and consider restricting local user access to Foxit Reader installations where possible. The vulnerability demonstrates the importance of proper memory access controls and input validation in service components, particularly those that operate with elevated privileges. Organizations should also consider implementing the principle of least privilege for the Foxit Cloud Update Service, limiting its access rights to only those resources necessary for legitimate update operations. This vulnerability serves as a reminder of the critical need for secure coding practices in system services and the potential consequences of inadequate memory management in applications that handle update mechanisms, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploits and T1059 which covers execution through system services.