CVE-2017-8256 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, array out of bounds access can occur if userspace sends more than 16 multicast addresses.
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Analysis
by VulDB Data Team • 11/09/2019
The vulnerability identified as CVE-2017-8256 represents a critical array out of bounds access flaw that affects Qualcomm products running Android versions based on the Linux kernel. This issue stems from improper validation of multicast address parameters within the kernel's network stack implementation, creating a potential avenue for denial of service attacks and system instability. The flaw specifically manifests when userspace applications attempt to configure more than 16 multicast addresses, triggering undefined behavior in the underlying kernel code.
The technical root cause of this vulnerability lies in the insufficient bounds checking within the kernel's multicast address handling mechanisms. When the system receives a request containing more than the expected 16 multicast addresses, the kernel's array indexing operations exceed their allocated memory boundaries, leading to memory corruption and potential system crashes. This type of vulnerability falls under the CWE-129 weakness category, which specifically addresses insufficient bounds checking in array access operations. The flaw demonstrates a classic buffer overflow pattern where the kernel fails to validate input parameters against predefined limits, allowing malicious or malformed input to cause unintended memory access patterns.
From an operational perspective, this vulnerability presents significant risks to mobile device stability and security. Attackers could exploit this weakness to cause system crashes, leading to denial of service conditions that would render devices unusable until reboot. The impact extends beyond simple service disruption as memory corruption could potentially enable privilege escalation or arbitrary code execution under certain conditions. Given that Qualcomm's products power numerous Android devices globally, the potential attack surface is extensive, affecting millions of end users and enterprise deployments. The vulnerability operates at the kernel level, making it particularly dangerous as it can bypass standard user-space protections and security mechanisms.
Mitigation strategies for CVE-2017-8256 should focus on both immediate patching and operational hardening measures. Qualcomm has released security updates that include proper bounds checking for multicast address arrays, ensuring that input validation prevents array overflow conditions. Organizations should prioritize applying these patches to all affected devices and systems, particularly those in critical infrastructure environments. Network monitoring should include detection of unusual multicast address configurations that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under the 'Exploitation for Privilege Escalation' and 'Denial of Service' tactics, highlighting the need for comprehensive security monitoring and incident response procedures. Additionally, implementing kernel memory protection mechanisms such as stack canaries and address space layout randomization can provide additional defense-in-depth measures against similar vulnerabilities.