CVE-2025-2884 in TPM2.0
Summary
by MITRE • 06/10/2025
TCG TPM2.0 Reference implementation's CryptHmacSign helper function is vulnerable to Out-of-Bounds read due to the lack of validation the signature scheme with the signature key's algorithm. See Errata 1.83 of TCG standard TPM2.0
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Analysis
by VulDB Data Team • 10/28/2025
The vulnerability identified as CVE-2025-2884 affects the TCG TPM2.0 Reference Implementation's CryptHmacSign helper function, representing a critical security flaw that undermines the integrity of cryptographic operations within Trusted Platform Module implementations. This issue stems from insufficient validation mechanisms that fail to properly verify the compatibility between signature schemes and the underlying key algorithms, creating a pathway for malicious actors to exploit the system through improper cryptographic handling.
The technical flaw manifests as an out-of-bounds read condition within the CryptHmacSign function where the implementation does not adequately validate whether the specified signature scheme aligns with the signature key's algorithm. This validation gap allows for potential buffer over-read scenarios that can be leveraged to extract sensitive information from memory or potentially disrupt system operations. The vulnerability is particularly concerning because it occurs at the cryptographic primitive level, where such flaws can compromise the fundamental security guarantees that TPM implementations are designed to provide.
The operational impact of this vulnerability extends beyond simple data exposure, as it can enable attackers to perform advanced persistent attacks that exploit the cryptographic weaknesses in TPM implementations. An attacker who successfully exploits this vulnerability could potentially gain unauthorized access to cryptographic keys, manipulate signed data, or extract confidential information from the TPM's memory space. The nature of this flaw means that systems relying on TPM2.0 for security operations may be vulnerable to sophisticated attacks that bypass traditional security controls.
This vulnerability maps directly to CWE-129, which describes improper validation of array index values, and represents a clear violation of the principle of input validation that is fundamental to secure cryptographic implementations. The issue also aligns with ATT&CK technique T1552.001, which covers credentials from password storage providers, as compromised cryptographic operations can lead to credential exposure. Additionally, the vulnerability demonstrates weaknesses in the TCG TPM2.0 standard implementation that can be exploited through the T1059.001 technique of command and scripting interpreter, as attackers may leverage the out-of-bounds read to execute unauthorized code within the cryptographic context.
Mitigation strategies should focus on implementing proper validation checks within the CryptHmacSign function to ensure that signature schemes are compatible with the corresponding key algorithms before cryptographic operations are performed. System administrators should update to patched versions of the TCG TPM2.0 Reference Implementation that address this validation gap. Organizations should also conduct thorough security assessments of their TPM implementations to identify any other potential cryptographic weaknesses that may have similar validation issues. The fix should include comprehensive input validation that checks the compatibility between signature schemes and key algorithms, ensuring that the cryptographic operations adhere to the TCG TPM2.0 standard requirements as specified in Errata 1.83.