CVE-2025-29949: AMD Secure Processor DoS Vulnerability

CVE-2025-29949 Overview

CVE-2025-29949 is an out-of-bounds write vulnerability affecting the AMD Secure Processor (ASP) Boot Loader when operating in legacy recovery mode. The vulnerability stems from insufficient input parameter sanitization, which allows an attacker with local access to write beyond intended memory boundaries and corrupt Secure DRAM. This memory corruption can potentially result in denial of service conditions affecting the system's secure boot process.

Critical Impact

Local attackers with low-level system access can corrupt Secure DRAM through out-of-bounds writes in AMD Secure Processor Boot Loader legacy recovery mode, potentially causing denial of service.

Affected Products

• AMD Secure Processor (ASP) Boot Loader (legacy recovery mode)
• AMD systems utilizing ASP Boot Loader with legacy recovery functionality

Discovery Timeline

• 2026-02-10 - CVE-2025-29949 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2025-29949

Vulnerability Analysis

This vulnerability is classified under CWE-787 (Out-of-Bounds Write), a memory corruption weakness that occurs when software writes data past the end, or before the beginning, of an intended buffer. In the context of CVE-2025-29949, the AMD Secure Processor Boot Loader fails to properly sanitize input parameters when operating in legacy recovery mode.

The AMD Secure Processor (ASP) is a dedicated security coprocessor embedded in AMD CPUs that handles sensitive cryptographic operations and secure boot validation. The Boot Loader component is responsible for initializing the secure environment and loading subsequent firmware components. When the system enters legacy recovery mode, the Boot Loader processes input parameters that, due to insufficient validation, can be manipulated to trigger writes outside the designated Secure DRAM boundaries.

The exploitation requires local access to the target system with low privileges. While the attack complexity is low, the impact is constrained to availability disruption through memory corruption. The vulnerability does not appear to enable confidentiality or integrity breaches based on the available analysis.

Root Cause

The root cause of CVE-2025-29949 lies in inadequate input parameter sanitization within the ASP Boot Loader code path specifically triggered during legacy recovery mode operations. When processing certain input parameters, the Boot Loader fails to validate that the resulting memory write operations remain within the bounds of allocated Secure DRAM regions. This missing boundary check allows crafted inputs to cause the processor to write data to unintended memory locations, corrupting the secure memory space.

Attack Vector

The attack vector is local, requiring the attacker to have direct access to the vulnerable system. The exploitation scenario involves:

1. An attacker with local access and low-level privileges targets a system with an AMD processor containing the vulnerable ASP Boot Loader
2. The attacker triggers the legacy recovery mode functionality, potentially through specific system states or boot configurations
3. Malicious input parameters are passed to the Boot Loader that exploit the insufficient sanitization
4. The unsanitized parameters cause the Boot Loader to perform out-of-bounds write operations
5. Secure DRAM is corrupted, potentially causing the system to become unresponsive or fail secure boot validation

The vulnerability specifically manifests only when the ASP Boot Loader operates in legacy recovery mode, limiting the attack surface to scenarios where this mode is actively engaged. Technical details regarding specific parameter manipulation techniques should be referenced in the AMD Security Bulletin #4013.

Detection Methods for CVE-2025-29949

Indicators of Compromise

• Unexpected system crashes or reboots during boot sequences, particularly when recovery mode is involved
• Secure boot validation failures without clear configuration changes
• Anomalous behavior during AMD Secure Processor initialization phases
• System logs indicating memory corruption or ASP-related errors

Detection Strategies

• Monitor system event logs for unexpected ASP Boot Loader errors or recovery mode activations
• Implement firmware integrity verification to detect unauthorized modifications to boot components
• Deploy hardware-level monitoring for secure enclave anomalies where available
• Utilize SentinelOne's endpoint detection capabilities to identify unusual boot-time behavior patterns

Monitoring Recommendations

• Enable verbose logging for firmware and boot processes to capture ASP-related events
• Establish baseline behavior for system boot sequences to identify deviations
• Configure alerts for repeated recovery mode activations which may indicate exploitation attempts
• Monitor for denial of service conditions that correlate with boot or recovery operations

How to Mitigate CVE-2025-29949

Immediate Actions Required

• Review the AMD Security Bulletin #4013 for vendor-specific guidance and affected product lists
• Inventory systems with AMD processors to identify potentially vulnerable deployments
• Apply firmware updates from AMD or system vendors as they become available
• Restrict physical and local access to critical systems to reduce attack surface
• Implement defense-in-depth strategies to limit the impact of potential exploitation

Patch Information

AMD has published Security Bulletin #4013 addressing this vulnerability. Organizations should consult the AMD Security Bulletin #4013 for detailed patch information, affected processor models, and updated firmware versions. Firmware updates should be applied through system vendor channels (OEM BIOS/UEFI updates) as ASP firmware is typically distributed as part of platform firmware packages.

Workarounds

• Limit local access to affected systems to trusted administrators only
• Disable legacy recovery mode functionality if not operationally required and if such configuration is supported
• Implement physical security controls to prevent unauthorized local access
• Monitor for and alert on recovery mode activation events as a compensating control