tpm2-tss is an open source software implementation of the Trusted Computing Group (TCG) Trusted Platform Module (TPM) 2 Software Stack (TSS2). In affected versions `Tss2_RC_SetHandler` and `Tss2_RC_Decode` both index into `layer_handler` with an 8 bit layer number, but the array only has `TPM2_ERROR_TSS2_RC_LAYER_COUNT` entries, so trying to add a handler for higher-numbered layers or decode a response code with such a layer number reads/writes past the end of the buffer. This Buffer overrun, could result in arbitrary code execution. An example attack would be a MiTM bus attack that returns 0xFFFFFFFF for the RC. Given the common use case of TPM modules an attacker must have local access to the target machine with local system privileges which allows access to the TPM system. Usually TPM access requires administrative privilege.
Metrics
CVSS Version: 3.1 |
Base Score: 6.4 MEDIUM Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
l➤ Exploitability Metrics: Attack Vector (AV)* LOCAL Attack Complexity (AC)* HIGH Privileges Required (PR)* HIGH User Interaction (UI)* NONE Scope (S)* UNCHANGED
l➤ Impact Metrics: Confidentiality Impact (C)* HIGH Integrity Impact (I)* HIGH Availability Impact (A)* HIGH
Weakness Enumeration (CWE)
CWE-ID: CWE-120 CWE Name: CWE-120: Buffer Copy without Checking Size of Input (
Classic Buffer Overflow
) Source: tpm2-software
Common Attack Pattern Enumeration and Classification (CAPEC)