CVE-2020-8753: Intel AMT Information Disclosure Flaw

CVE-2020-8753 Overview

CVE-2020-8753 is an out-of-bounds read vulnerability in the DHCP subsystem of Intel Active Management Technology (AMT) and Intel Standard Manageability (ISM) firmware. This flaw affects multiple firmware versions before 11.8.80, 11.12.80, 11.22.80, 12.0.70, and 14.0.45, and may allow an unauthenticated user to potentially enable information disclosure via network access.

Critical Impact

This vulnerability enables unauthenticated attackers to exploit the DHCP subsystem remotely over the network, potentially exposing sensitive information from memory regions outside the intended bounds.

Affected Products

• Intel Active Management Technology Firmware (versions before 11.8.80, 11.12.80, 11.22.80, 12.0.70, and 14.0.45)
• Intel Standard Manageability (versions before 11.8.80, 11.12.80, 11.22.80, 12.0.70, and 14.0.45)

Discovery Timeline

• November 12, 2020 - CVE-2020-8753 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-8753

Vulnerability Analysis

The vulnerability resides in the DHCP subsystem of Intel AMT and Intel ISM firmware. DHCP (Dynamic Host Configuration Protocol) is used to automatically assign IP addresses and network configuration to devices. The out-of-bounds read condition (CWE-125) occurs when the DHCP subsystem improperly handles input data, allowing read operations beyond the allocated memory buffer boundaries.

This type of vulnerability can result in the disclosure of sensitive information stored in adjacent memory regions. Since Intel AMT operates at a firmware level with significant system access privileges, an attacker exploiting this flaw could potentially access confidential data including configuration information, cryptographic material, or other sensitive system details.

The network-based attack vector means that any unauthenticated attacker with network access to the vulnerable DHCP subsystem can potentially trigger this vulnerability without requiring any user interaction or special privileges.

Root Cause

The root cause is improper bounds checking in the DHCP subsystem when processing network packets. When handling DHCP messages, the firmware fails to properly validate the length of input data against the allocated buffer size, allowing read operations to extend beyond the intended memory boundaries. This is classified as CWE-125 (Out-of-bounds Read).

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can craft malicious DHCP packets and send them to a system running vulnerable Intel AMT or ISM firmware. When the DHCP subsystem processes these specially crafted packets, it may read data from memory locations outside the intended buffer, potentially leaking sensitive information back to the attacker.

The vulnerability is particularly concerning because Intel AMT operates at the firmware level, meaning it functions independently of the operating system and can be accessed even when the system is powered off (in certain configurations). This makes detection and defense more challenging than typical software vulnerabilities.

Detection Methods for CVE-2020-8753

Indicators of Compromise

• Anomalous DHCP traffic patterns targeting Intel AMT-enabled systems
• Unusual network activity on ports associated with Intel AMT management (typically ports 16992-16995)
• Unexpected DHCP requests or responses with malformed packet structures
• Evidence of reconnaissance or scanning activity targeting Intel AMT services

Detection Strategies

• Monitor network traffic for malformed or suspicious DHCP packets directed at Intel AMT-enabled endpoints
• Implement network intrusion detection signatures for out-of-bounds read exploitation attempts in DHCP traffic
• Audit firmware versions across enterprise systems to identify vulnerable Intel AMT/ISM installations
• Deploy network segmentation to isolate AMT management traffic and enable focused monitoring

Monitoring Recommendations

• Enable logging for Intel AMT management interfaces and regularly review for suspicious activity
• Implement network-level monitoring for unusual DHCP traffic patterns or packet sizes
• Configure alerts for unauthorized access attempts to Intel AMT management ports
• Regularly audit and inventory Intel AMT firmware versions across the enterprise

How to Mitigate CVE-2020-8753

Immediate Actions Required

• Update Intel AMT firmware to version 11.8.80, 11.12.80, 11.22.80, 12.0.70, or 14.0.45 or later depending on your version branch
• Review the Intel Security Advisory SA-00391 for specific guidance on affected versions
• Restrict network access to Intel AMT management interfaces using firewall rules
• Disable Intel AMT on systems where it is not required

Patch Information

Intel has released firmware updates to address this vulnerability. Organizations should consult the Intel Security Advisory SA-00391 for detailed patch information and download links. The NetApp Security Advisory NTAP-20201113-0003 also provides relevant guidance for NetApp products affected by this vulnerability.

Firmware updates should be applied through standard system management tools or BIOS/UEFI update mechanisms provided by the system manufacturer.

Workarounds

• Disable Intel AMT if the feature is not required for business operations
• Implement network segmentation to isolate Intel AMT traffic from untrusted networks
• Configure firewall rules to restrict DHCP traffic to Intel AMT interfaces from untrusted sources
• Use out-of-band management networks to separate AMT traffic from production networks

# Example: Restrict access to Intel AMT ports using iptables
# Block incoming traffic to AMT management ports from untrusted networks
iptables -A INPUT -p tcp --dport 16992:16995 -s <trusted_network> -j ACCEPT
iptables -A INPUT -p tcp --dport 16992:16995 -j DROP
iptables -A INPUT -p udp --dport 16992:16995 -s <trusted_network> -j ACCEPT
iptables -A INPUT -p udp --dport 16992:16995 -j DROP