CWE-1292: Incorrect Conversion of Security Identifiers

How it's found

Incorrect Conversion of Security Identifiers is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.

In a System-On-Chip (SoC), various integrated circuits and hardware engines generate transactions such as to access (reads/writes) assets or perform certain actions (e.g., reset, fetch, compute, etc.). Among various types of message information, a typical transaction is comprised of source identity (to identify the originator of the transaction) and a destination identity (to route the transaction to the respective entity). Sometimes the transactions are qualified with a security identifier. This security identifier helps the destination agent decide on the set of allowed actions (e.g., access an asset for read and writes). A typical bus connects several leader and follower agents. Some follower agents implement bus protocols differently from leader agents. A protocol conversion happens at a bridge to seamlessly connect different protocols on the bus. One example is a system that implements a leader with the Advanced High-performance Bus (AHB) protocol and a follower with the Open-Core Protocol (OCP). A bridge AHB-to-OCP is needed to translate the transaction from one form to the other. A common weakness that can exist in this scenario is that this conversion between protocols is implemented incorrectly, whereupon an untrusted agent may gain unauthorized access to an asset.

Vulnerable vs. safe

In AHB-to-OCP bridge, the security identifier information conversion is done incorrectly.

The conversion of the signals from one protocol (AHB) to another (OCP) must be done while preserving the security identifier correctly.

Consequences

• Modify Memory, Read Memory, DoS: Resource Consumption (Other), Execute Unauthorized Code or Commands, Gain Privileges or Assume Identity, Quality Degradation

Mitigations

• Architecture and Design: Security identifier decoders must be reviewed for design inconsistency and common weaknesses.
• Implementation: Access and programming flows must be tested in pre-silicon and post-silicon testing.

Where this fits in a TurboPentest engagement

This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.

Frequently asked questions

Related CWEs

• Pillar weakness
  CWE-284: Improper Access Control
• Class weakness
  CWE-1294: Insecure Security Identifier Mechanism