13 vulnerabilities classified as CWE-1242. AI Chinese analysis included.
CWE-1242 represents a design weakness where hardware or firmware includes undocumented features, often called "chicken bits," which can inadvertently create unauthorized access vectors. These bits are typically embedded to facilitate rapid identification and isolation of faulty components during manufacturing or debugging, allowing developers to quickly disable specific functional security features. However, if these mechanisms remain accessible in production environments, attackers can exploit them to bypass critical security controls, effectively disabling protections like secure boot or encryption modules. To mitigate this risk, developers must rigorously audit firmware and hardware designs to ensure all undocumented features are permanently disabled or physically fused off before release. Strict access controls and comprehensive documentation reviews are essential to prevent these hidden entry points from being leveraged by malicious actors seeking to compromise system integrity.
Attackers dump the code from the device and then perform reverse engineering to analyze the code. The undocumented, special-access features are identified, and attackers can activate them by sending specific commands via UART before secure-boot phase completes. Using these hidden features, attackers can perform reads and writes to memory via the UART interface. At runtime, the attackers can also execute arbitrary code and dump the entire memory contents.Vulnerabilities classified as CWE-1242 represent 13 CVEs. The CWE taxonomy describes the weakness; review individual CVEs for product-specific impact.