CVE-2016-10467 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Automobile and Snapdragon Mobile SD 210/SD 212/SD 205, SD 400, SD 410/12, SD 615/16/SD 415, SD 617, SD 650/52, SD 800, SD 808, SD 820, and SD 820A, function ce_pkcs1_pss_padding_verify_auto_recover_saltlen assumes that the size of the encoded message is equal to the size of the RSA modulus. This assumption is true for most RSA keys, but it fails when modulus_bitlen % 8 == 1.
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Analysis
by VulDB Data Team • 01/27/2020
This vulnerability exists in Qualcomm Snapdragon chipsets used in Android devices and represents a cryptographic flaw that could compromise the security of digital signatures and authentication mechanisms. The issue affects devices running Android versions prior to the 2018-04-05 security patch level, specifically targeting Snapdragon Automotive and Mobile platforms including various SD 210/212/205, SD 400, SD 410/12, SD 615/16/415, SD 617, SD 650/52, SD 800, SD 808, SD 820, and SD 820A chipsets. The vulnerability stems from an incorrect assumption in the cryptographic implementation that directly impacts the RSA padding verification process.
The technical flaw occurs within the function ce_pkcs1_pss_padding_verify_auto_recover_saltlen which processes PKCS#1 v1.5 and PSS padding schemes for RSA signatures. This function makes a critical assumption that the encoded message size matches exactly the RSA modulus size, which holds true for most RSA key sizes but fails when the modulus bit length has a remainder of 1 when divided by 8. This specific mathematical condition creates a scenario where the padding verification logic incorrectly processes the signature data, potentially allowing malformed signatures to be accepted as valid. The vulnerability falls under CWE-20, "Improper Input Validation," and specifically relates to improper handling of cryptographic parameters that should be validated before processing.
The operational impact of this vulnerability is significant as it could enable attackers to forge digital signatures or bypass authentication mechanisms that rely on RSA-PSS padding verification. This weakness particularly affects secure boot processes, firmware updates, and other security-critical operations that depend on proper signature validation. Attackers could exploit this to perform unauthorized firmware modifications, bypass device security measures, or conduct man-in-the-middle attacks against secure communications. The vulnerability represents a fundamental flaw in the cryptographic implementation that could undermine the entire security architecture of affected devices, particularly those in automotive applications where security is paramount.
Mitigation strategies should focus on applying the latest security patches from Qualcomm and Android vendors, which address the specific mathematical edge case in the padding verification logic. Organizations should also implement comprehensive device inventory management to identify all affected Snapdragon chipsets and ensure timely patch deployment. Additional defensive measures include monitoring for suspicious signature validation activities, implementing network-based intrusion detection systems, and maintaining strict update policies for mobile device management. The ATT&CK framework categorizes this vulnerability under T1552.001 "Unsecured Credentials" and T1059.001 "Command and Scripting Interpreter" as it could enable privilege escalation and unauthorized code execution. Regular security audits of cryptographic implementations and adherence to NIST SP 800-57 standards for key management would further reduce the risk exposure associated with such implementation flaws.