CVE-2018-11856 in Snapdragon Mobile
Summary
by MITRE
Improper input validation leads to buffer overwrite in the WLAN function that handles WMI commands in Snapdragon Mobile in version SD 835, SD 845, SD 850.
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Analysis
by VulDB Data Team • 06/03/2023
The vulnerability identified as CVE-2018-11856 represents a critical buffer overflow condition within the wireless local area network functionality of Qualcomm Snapdragon mobile processors. This flaw specifically affects the Wireless Microcontroller Interface (WMI) command handling mechanism that operates within the Snapdragon 835, 845, and 850 chipsets. The issue stems from inadequate input validation procedures that fail to properly sanitize or verify the size and content of incoming WMI commands before processing them within memory buffers. This improper validation creates a scenario where maliciously crafted input data can exceed the allocated buffer boundaries, leading to memory corruption and potential arbitrary code execution. The vulnerability exists at the intersection of wireless communication protocols and embedded system security, making it particularly dangerous in mobile environments where wireless connectivity is fundamental to device operation.
The technical implementation of this vulnerability manifests through the WMI command processing subsystem within the Snapdragon SoC architecture. When the wireless microcontroller receives WMI commands, the system fails to validate the length of incoming data structures against predetermined buffer limits. This allows an attacker to submit oversized command payloads that overwrite adjacent memory regions, potentially corrupting critical system data structures or executable code segments. The flaw operates at a low system level within the kernel or driver components responsible for wireless communication, making exploitation particularly stealthy and difficult to detect through conventional security monitoring. The buffer overflow can result in system crashes, unauthorized privilege escalation, or complete system compromise depending on the execution context and memory layout. This vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflows, though the specific implementation in this case involves memory corruption within kernel-level wireless subsystems.
The operational impact of CVE-2018-11856 extends beyond simple system instability to encompass significant security implications for mobile device users and enterprise environments. Mobile devices running affected Snapdragon processors become susceptible to remote exploitation through wireless network protocols, potentially allowing attackers to gain unauthorized access to sensitive device functions and data. The vulnerability's presence in widely deployed chipsets like the Snapdragon 835, 845, and 850 means that millions of devices could be at risk, particularly those in enterprise settings where wireless communication is prevalent. Attackers could leverage this vulnerability to execute malicious code with elevated privileges, potentially accessing encrypted data, intercepting communications, or establishing persistent backdoors within affected devices. The attack surface is particularly concerning given that WMI commands are frequently transmitted over wireless networks and may be processed automatically without user interaction, making the attack vector both remote and potentially automated. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, and T1068 for exploit for privilege escalation, demonstrating the multi-faceted nature of the security threat.
Mitigation strategies for CVE-2018-11856 require a multi-layered approach combining immediate patch management with operational security measures. Qualcomm released security updates specifically addressing this vulnerability through their regular security bulletins, and device manufacturers were advised to implement these patches promptly across affected device fleets. System administrators should prioritize updating firmware and operating system components to ensure the patched WMI command processing routines are in place. Network monitoring solutions should be enhanced to detect anomalous WMI command patterns that might indicate exploitation attempts, while also implementing network segmentation to limit wireless communication exposure. Device hardening measures including disabling unnecessary wireless functions, implementing secure boot mechanisms, and deploying mobile threat defense solutions can help reduce the attack surface. Organizations should also consider implementing behavioral monitoring to detect system instability or unexpected memory corruption patterns that might indicate exploitation of this buffer overflow vulnerability. The remediation process must account for the fact that this vulnerability affects the core wireless communication subsystem, requiring careful testing of patches to ensure they do not disrupt essential wireless functionality while providing adequate protection against the buffer overflow condition.