CVE-2017-18173 in Snapdragon Mobile
Summary
by MITRE
In case of using an invalid android verified boot signature with very large length, an integer underflow occurs in Snapdragon Mobile in SD 425, SD 427, SD 430, SD 435, SD 450, SD 625, SD 810, SD 820, SD 835, SDM630, SDM636, SDM660, Snapdragon_High_Med_2016.
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Analysis
by VulDB Data Team • 09/12/2023
This vulnerability represents a critical integer underflow condition that affects multiple Qualcomm Snapdragon mobile platform variants including the SD 425, SD 427, SD 430, SD 435, SD 450, SD 625, SD 810, SD 820, SD 835, SDM630, SDM636, and SDM660 chipsets. The flaw occurs specifically when processing android verified boot signatures with excessively large length values, creating a scenario where the system's integer arithmetic fails to properly handle boundary conditions. This vulnerability resides within the Snapdragon Mobile platform's security subsystem and represents a fundamental flaw in input validation mechanisms. The integer underflow condition arises from the failure to properly validate signature length parameters during the verified boot process, which is a critical security feature designed to ensure device integrity and prevent unauthorized modifications to the boot chain.
The technical exploitation of this vulnerability occurs when an attacker presents a malformed android verified boot signature with an abnormally large length value that causes the system's integer variables to wrap around to negative values. This underflow condition can potentially lead to memory corruption and arbitrary code execution within the secure boot environment. The vulnerability is particularly concerning because it affects the foundational security mechanisms of mobile devices, potentially allowing attackers to bypass critical security checks that protect against malicious firmware modifications. The flaw demonstrates poor input validation practices and inadequate boundary checking within the platform's security implementation. According to CWE classification, this represents a CWE-190: Integer Overflow or Wraparound vulnerability that occurs when a calculation produces a result that is larger than the maximum value that can be represented by the data type. The impact extends beyond simple integer arithmetic failures to potentially compromise the entire device boot integrity.
From an operational perspective, this vulnerability creates a significant risk for mobile device security as it can be exploited to undermine the android verified boot process that ensures only trusted code executes during device startup. Attackers could potentially leverage this flaw to install malicious bootloaders or modify system partitions, effectively bypassing the security controls that protect against rootkits and other persistent malware. The vulnerability affects devices running on Qualcomm's Snapdragon platforms, which are widely deployed across numerous smartphone and tablet models, making the potential attack surface extremely broad. The exploitation requires minimal privileges and can be executed through specially crafted malicious signatures, potentially allowing for complete device compromise. This vulnerability directly impacts the ATT&CK technique T1014: Rootkit, as it provides a pathway for establishing persistent malicious control over device boot processes. The integer underflow creates memory corruption that can be leveraged for privilege escalation and persistent access to the device.
Mitigation strategies for this vulnerability require immediate firmware updates from device manufacturers to address the integer underflow condition in the Snapdragon platform's verified boot implementation. System administrators and device users should ensure all available security patches are applied promptly, as the vulnerability affects multiple generations of Qualcomm's mobile platforms. The fix typically involves implementing proper input validation for signature length parameters and ensuring integer arithmetic operations include appropriate overflow checks. Device manufacturers should also implement enhanced monitoring for suspicious signature validation attempts and consider implementing additional security layers beyond the basic verified boot mechanism. Organizations should review their mobile device management policies to ensure proper patch deployment and monitoring of vulnerable platforms. The vulnerability highlights the importance of robust input validation and proper integer handling in security-critical systems, particularly those involved in boot process integrity verification. Regular security assessments of mobile platform components should include thorough examination of arithmetic operations and boundary condition handling to prevent similar vulnerabilities from being introduced in future implementations.