CVE-2022-26872: AMI MegaRAC SP-X Auth Bypass Vulnerability

CVE-2022-26872 Overview

CVE-2022-26872 is a high-severity vulnerability affecting AMI MegaRAC SP-X firmware that enables password reset interception via the BMC API. This vulnerability falls under CWE-640 (Weak Password Recovery Mechanism for Forgotten Password), allowing attackers to intercept or manipulate password reset processes in baseboard management controller (BMC) environments.

The vulnerability exists in the password reset functionality exposed through the MegaRAC SP-X API. An attacker with network access who can position themselves to intercept password reset requests can potentially hijack user accounts, gaining unauthorized access to critical BMC management interfaces that control server hardware operations.

Critical Impact

Successful exploitation allows attackers to intercept password reset tokens and take over BMC administrator accounts, potentially enabling full control of server hardware including power management, console access, and firmware operations.

Affected Products

• AMI MegaRAC SP-X version 12
• AMI MegaRAC SP-X version 13

Discovery Timeline

• 2023-01-30 - CVE-2022-26872 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-26872

Vulnerability Analysis

This vulnerability targets the password reset mechanism within AMI MegaRAC SP-X firmware, which is widely deployed as the baseboard management controller (BMC) solution across numerous server platforms from major OEMs. The weakness allows an attacker to intercept password reset operations conducted through the BMC's API interface.

BMC controllers provide out-of-band management capabilities for servers, including remote power control, console access, hardware monitoring, and firmware updates. Compromising BMC authentication can grant attackers persistent, hardware-level access to servers that persists even across operating system reinstallations.

The vulnerability requires user interaction—specifically, a legitimate user must initiate a password reset operation. An attacker positioned to intercept network traffic can capture the password reset token or link, then use it to set a new password before the legitimate user completes the process.

Root Cause

The root cause is a weak password recovery mechanism (CWE-640) in the MegaRAC SP-X firmware's API implementation. The password reset process lacks adequate protections against interception, such as insufficient token entropy, lack of secure token transmission, or inadequate validation of the requester's identity during the reset process.

Attack Vector

This vulnerability is network-exploitable and requires the attacker to have network visibility to the BMC management interface. The attack scenario involves:

1. The attacker monitors network traffic to BMC interfaces or positions themselves to intercept API communications
2. A legitimate administrator initiates a password reset through the BMC web interface or API
3. The attacker intercepts the password reset token or link transmitted during the reset process
4. Using the intercepted credentials, the attacker completes the password reset before the legitimate user
5. The attacker gains access to the BMC with administrator privileges

The vulnerability requires user interaction as the attack depends on a legitimate password reset being initiated. However, social engineering techniques could be employed to trick administrators into initiating password resets, making the user interaction requirement less of a barrier in targeted attacks.

Detection Methods for CVE-2022-26872

Indicators of Compromise

• Multiple password reset requests originating from different network sources for the same BMC account
• Password reset tokens being redeemed from IP addresses different from those that initiated the reset
• Unusual BMC login activity following password reset operations
• Administrative access to BMC from unexpected network locations

Detection Strategies

• Monitor BMC authentication logs for password reset events followed by logins from unexpected IP addresses
• Implement network monitoring for unusual patterns in BMC API traffic, particularly around password reset endpoints
• Configure alerts for multiple failed password reset attempts or rapid successive reset requests
• Deploy network segmentation and monitor for unauthorized access to BMC management networks

Monitoring Recommendations

• Enable comprehensive logging on all BMC interfaces and forward logs to a centralized SIEM
• Monitor for anomalous API calls to password reset endpoints on MegaRAC SP-X devices
• Track changes to BMC user accounts and alert on unauthorized modifications
• Implement network traffic analysis on out-of-band management networks to detect interception attempts

How to Mitigate CVE-2022-26872

Immediate Actions Required

• Review the AMI Security Advisory 2023-001 for specific patch information and affected versions
• Isolate BMC management interfaces on dedicated, secured network segments
• Audit all BMC user accounts and disable unnecessary accounts
• Enable TLS encryption for all BMC communications and API traffic

Patch Information

AMI has released security updates to address this vulnerability. Organizations should consult the AMI Security Advisory 2023-001 for specific patch details and version information. Server OEMs may distribute these patches through their own firmware update channels, so administrators should also check with their hardware vendors for applicable updates.

Additional guidance is available from CERT Vulnerability Report #730007 and the NetApp Security Advisory NTAP-20230731-0008 for affected NetApp products.

Workarounds

• Restrict BMC network access to dedicated management VLANs with strict access controls
• Implement strong authentication mechanisms and avoid using the password reset functionality when possible
• Use VPN or other encrypted tunnels for all BMC management traffic
• Disable remote password reset functionality if not operationally required, requiring physical access for account recovery

# Network segmentation recommendation for BMC interfaces
# Ensure BMC interfaces are isolated on a dedicated management network
# Example firewall rule to restrict BMC access to management hosts only

# Allow BMC access only from designated management workstations
iptables -A INPUT -p tcp -s 10.0.100.0/24 --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP