CVE-2015-9208 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Mobile and Snapdragon Wear IPQ4019, MDM9206, MDM9607, MDM9635M, MDM9640, MDM9645, MSM8909W, SD 210/SD 212/SD 205, SD 400, SD 410/12, SD 615/16/SD 415, SD 800, and SD 810, the function tzbsp_pil_verify_sig() does not strictly check that the pointer to ELF and program headers and hash segment is within secure memory. It only checks that the address is not in non-secure memory. A given address range can overlap with both secure and non-secure regions - hence if such an address is passed in, it would not pass the non-secure range check, and would be considered valid by the function, even though that memory area could be modified by the non-secure side.
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Analysis
by VulDB Data Team • 01/26/2020
The vulnerability described in CVE-2015-9208 represents a critical security flaw in Qualcomm Snapdragon mobile platforms that affects Android devices released before the 2018-04-05 security patch level. This issue resides within the trusted execution environment of the device's secure processing unit, specifically in the tzbsp_pil_verify_sig() function that handles signature verification for firmware components. The vulnerability stems from insufficient memory validation mechanisms that fail to properly verify the integrity of memory regions containing ELF headers, program headers, and hash segments used during the secure boot process.
The technical flaw manifests in the function's inadequate memory boundary checking approach, which only validates that memory addresses fall outside of non-secure memory regions rather than ensuring complete isolation within secure memory boundaries. This permissive validation allows for memory address ranges that overlap both secure and non-secure regions to pass the verification check, creating a potential attack vector where malicious code could manipulate memory contents that should remain protected. The vulnerability specifically impacts Qualcomm Snapdragon platforms including the SD 210/SD 212/SD 205, SD 400, SD 410/12, SD 615/16/SD 415, SD 800, and SD 810 chipsets, along with various MDM and IPQ4019 platforms, making it widespread across numerous mobile devices.
The operational impact of this vulnerability is significant as it undermines the fundamental security assumptions of the trusted execution environment, potentially allowing attackers to bypass secure boot processes and execute unauthorized code with elevated privileges. This weakness could enable malicious actors to modify firmware images, inject backdoors, or perform privilege escalation attacks that compromise the entire device security architecture. The vulnerability aligns with CWE-129, which addresses improper validation of array indices and buffer bounds, and represents a classic case of insufficient input validation in security-critical code paths. Attackers could exploit this through malicious firmware updates or by manipulating memory contents that are supposed to remain isolated within the secure domain.
The security implications extend beyond simple code execution, as this vulnerability compromises the integrity of the device's boot process and firmware verification mechanisms. According to ATT&CK framework techniques, this vulnerability maps to T1059.007 for execution through command and scripting interpreter and T1547.001 for privilege escalation through kernel exploits. The flaw essentially allows for a form of memory corruption attack where the non-secure side can manipulate secure memory regions, potentially enabling attacks such as firmware modification, rootkit installation, or complete device compromise. Organizations should prioritize patching affected devices and implementing additional runtime monitoring to detect potential exploitation attempts, while device manufacturers should review their secure boot implementations to ensure proper memory boundary validation and prevent similar vulnerabilities in future designs.