CVE-2020-5363: Dell Latitude 5300 Privilege Escalation Flaw

CVE-2020-5363 Overview

CVE-2020-5363 is a BIOS/UEFI vulnerability affecting select Dell Client Consumer and Commercial platforms. The vulnerability allows the BIOS Admin password to be changed through Dell's manageability interface without requiring knowledge of the current BIOS Admin password. This security flaw could potentially allow an unauthorized actor with physical access and/or OS administrator privileges to gain privileged access to the platform and the hard drive.

Critical Impact

An attacker with local access or OS administrator privileges can bypass BIOS password protection, potentially compromising system integrity, confidentiality, and availability at the firmware level.

Affected Products

• Dell Latitude 5300/5300 2-in-1 Firmware
• Dell Latitude 5400/5401 Firmware
• Dell Latitude 5500/5501 Firmware
• Dell Latitude 7200 2-in-1 Firmware
• Dell Latitude 7220/7220EX Rugged Extreme Tablet Firmware
• Dell Latitude 7300/7400 Firmware
• Dell Precision 3540/3541 Firmware
• Dell Precision 7540/7740 Firmware
• Dell XPS 13 9300 Firmware
• Dell XPS 7390 2-in-1 Firmware
• Dell XPS 7590 Firmware

Discovery Timeline

• June 10, 2020 - CVE-2020-5363 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-5363

Vulnerability Analysis

This vulnerability represents an authentication bypass flaw within Dell's BIOS manageability interface. The core issue lies in improper authentication enforcement when processing BIOS password change requests through the management interface. Under normal circumstances, changing the BIOS Admin password should require validation of the current password to prevent unauthorized modifications. However, this vulnerability allows the password change operation to proceed without such validation.

The vulnerability requires either physical access to the affected system or OS-level administrator privileges to exploit. Once exploited, an attacker gains the ability to modify BIOS settings, potentially disabling security features, installing persistent firmware-level malware, or gaining access to encrypted hard drive contents.

Root Cause

The root cause is classified under CWE-158 (Improper Neutralization of Null Byte or NUL Character) and categorized as NVD-CWE-Other, indicating an improper handling of authentication checks within Dell's manageability interface. The BIOS firmware fails to properly validate the current admin password before allowing password changes through the management interface, creating an authentication bypass condition.

Attack Vector

The attack requires local access to the target system. An attacker can exploit this vulnerability through two primary vectors:

1. Physical Access: An attacker with physical access to the device can interact with the manageability interface directly to modify the BIOS password without authentication.

2. OS Administrator Privileges: An attacker who has already compromised the operating system with administrative rights can leverage Dell's management tools or interfaces to send password change commands to the BIOS.

The exploitation does not require user interaction and has low attack complexity once the prerequisite access is obtained. Successful exploitation results in complete compromise of confidentiality, integrity, and availability of the affected platform.

Detection Methods for CVE-2020-5363

Indicators of Compromise

• Unexpected changes to BIOS configuration or boot settings
• BIOS password becoming unknown or changed without authorized administrator action
• Secure Boot settings disabled without proper authorization
• Unauthorized modifications to boot order or device priorities
• System event logs showing BIOS/firmware access from unexpected processes

Detection Strategies

• Monitor for use of Dell management utilities (such as Dell Command | Configure) by non-authorized processes or users
• Implement audit logging for BIOS configuration changes and review logs regularly
• Deploy endpoint detection solutions that monitor for firmware-level modifications
• Track administrative privilege escalation events that could precede exploitation
• Compare BIOS settings against known-good baseline configurations periodically

Monitoring Recommendations

• Enable BIOS event logging where supported and forward logs to centralized SIEM
• Monitor for unauthorized access to Dell management interfaces and tools
• Implement file integrity monitoring on Dell management utilities
• Alert on any BIOS password change events or attempts
• Conduct regular firmware integrity verification using hardware security modules or TPM attestation

How to Mitigate CVE-2020-5363

Immediate Actions Required

• Update BIOS firmware to the latest patched version from Dell immediately
• Restrict physical access to affected systems through appropriate physical security controls
• Limit OS administrator privileges to only trusted personnel and enforce least privilege
• Audit current BIOS settings and reset passwords on potentially compromised systems
• Enable TPM and Secure Boot features where available to detect unauthorized firmware changes

Patch Information

Dell has released firmware updates to address this vulnerability. Administrators should consult the Dell Support Article SLN321604 for specific firmware versions and download links for each affected model. Organizations should prioritize patching based on system exposure and criticality.

The patch addresses the authentication bypass by enforcing proper validation of the current BIOS Admin password before allowing any password changes through the manageability interface.

Workarounds

• Implement strict physical security controls to limit access to affected devices
• Restrict OS administrator access using role-based access control (RBAC)
• Disable or restrict access to Dell management interfaces where possible until patching is complete
• Enable chassis intrusion detection to alert on physical access attempts
• Consider using BIOS lock features and TPM-based attestation as defense-in-depth measures

# Example: Check Dell system firmware version using Dell Command | Monitor
# Run from elevated command prompt to identify systems requiring updates
dcmcli.exe /report:firmware

# Verify BIOS password status and configuration
dcmcli.exe /report:bios