AMI MegaRAC BMC authentication bypass enables remote code execution
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Authentication bypass in AMI MegaRAC BMC firmware allows unauthenticated remote code execution; proof-of-concept available.
A critical authentication bypass vulnerability has been discovered in AMI MegaRAC Software, a widely-deployed BMC firmware package used for out-of-band remote management of enterprise servers. The vulnerability exists in the Redfish Host Interface and allows an attacker to bypass authentication remotely, enabling complete server compromise. Successful exploitation grants attackers the ability to remotely control compromised servers, deploy malware and ransomware, tamper with firmware, brick motherboard components including BMC and BIOS/UEFI, cause physical damage through over-voltage attacks, and trigger indefinite reboot loops that victims cannot interrupt.
The vulnerability affects AMI UEFI versions prior to BKC_5.38 and AptioV versions prior to BKC_5.38, as well as specific versions of HPE Cray XD670 and ASUS RS720A systems. Proof-of-concept exploitation code has already been published by security firm Eclypsium, indicating active research and likely near-term weaponization. This is a critical vulnerability affecting infrastructure management layers, requiring immediate patching of affected systems.
Defenders should prioritize applying vendor-supplied updates immediately after testing, implement network segmentation to isolate BMC management interfaces, enforce the principle of least privilege, conduct vulnerability scanning and penetration testing of infrastructure management systems, and ensure robust vulnerability management and remediation processes are in place.
Mentioned in this report
Detection guidance
Redfish API BMC Account Creation or Modification via Web Request
Detects POST/PATCH/PUT requests to the Redfish AccountService accounts collection on a BMC web interface, a likely post-exploitation step after a MegaRAC Redfish authentication bypass to gain persistent BMC admin access. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Redfish API BMC Account Creation or Modification via Web Request
id: 3e6f7f73-142f-5f95-afea-ed8903b04596
status: experimental
description: Detects write requests (POST/PATCH/PUT) to the Redfish AccountService
Accounts endpoint on BMC or management web interfaces. After an authentication bypass
in AMI MegaRAC Redfish, creating or altering BMC accounts is a likely way to gain
persistent administrative access. Requires BMC, management-network proxy or reverse-proxy
web logs. Correlate with the source address not being a known management host.
tags:
- attack.initial-access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-method:
- POST
- PATCH
- PUT
cs-uri-stem|contains: /redfish/v1/AccountService/Accounts
condition: selection
falsepositives:
- Legitimate administrators or provisioning tooling (Ansible, vendor lifecycle managers)
creating or rotating BMC accounts from the management network
- Server onboarding automation during initial rack and stack
level: medium
author: Vorant
references:
- https://www.cisecurity.org/advisory/a-vulnerability-in-ami-megarac-software-could-allow-for-remote-code-execution_2025-028
Redfish API Firmware Update or Host Reset Action Request
Detects POST requests to Redfish UpdateService or ComputerSystem Reset actions, which an attacker with a BMC authentication bypass could use to tamper with firmware or force reboot loops. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Redfish API Firmware Update or Host Reset Action Request
id: 8d895a77-670b-51fc-a862-e34e0286d786
status: experimental
description: Detects POST requests to Redfish UpdateService actions or ComputerSystem
Reset actions on BMC web interfaces. Post-exploitation of an AMI MegaRAC Redfish
authentication bypass may involve flashing tampered BMC/BIOS firmware or repeatedly
resetting the host. Requires BMC, management-network proxy or reverse-proxy web
logs; baseline against change windows.
tags:
- attack.initial-access
- attack.t1190
logsource:
category: webserver
detection:
selection_method:
cs-method: POST
selection_uri:
cs-uri-stem|contains:
- /redfish/v1/UpdateService
- /Actions/ComputerSystem.Reset
condition: selection_method and selection_uri
falsepositives:
- Scheduled firmware maintenance performed by infrastructure teams or vendor lifecycle
tooling
- Orchestration platforms rebooting hosts through Redfish power actions
level: medium
author: Vorant
references:
- https://www.cisecurity.org/advisory/a-vulnerability-in-ami-megarac-software-could-allow-for-remote-code-execution_2025-028
Behavioural rules are generated from public reporting — validate in your environment before deploying.
Source reporting: https://www.cisecurity.org/advisory/a-vulnerability-in-ami-megarac-software-could-allow-for-remote-code-execution_2025-028
What this brief leaves out
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