CVE-2020-5366: Dell iDRAC9 Path Traversal Vulnerability

CVE-2020-5366 Overview

CVE-2020-5366 is a Path Traversal vulnerability affecting Dell EMC iDRAC9 firmware versions prior to 4.20.20.20. This security flaw allows a remote authenticated malicious user with low privileges to potentially exploit the vulnerability by manipulating input parameters to gain unauthorized read access to arbitrary files on the affected system.

The Integrated Dell Remote Access Controller (iDRAC) is a critical component for out-of-band server management, making this vulnerability particularly concerning for enterprise environments where iDRAC is used to manage server infrastructure remotely.

Critical Impact

Authenticated attackers with low privileges can read arbitrary files from the iDRAC9 system, potentially exposing sensitive configuration data, credentials, and system information critical to server management infrastructure.

Affected Products

• Dell iDRAC9 Firmware versions prior to 4.20.20.20
• Dell iDRAC9 Hardware (all models running vulnerable firmware)

Discovery Timeline

• July 9, 2020 - CVE-2020-5366 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-5366

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as Path Traversal or Directory Traversal. The flaw exists in the web interface of Dell EMC iDRAC9 firmware, where user-supplied input parameters are not properly validated before being used in file system operations.

An authenticated attacker with low-level privileges on the iDRAC9 management interface can craft malicious requests containing path traversal sequences (such as ../) to escape the intended directory structure and access files outside the web application's root directory. This allows unauthorized read access to sensitive system files that should not be accessible to low-privileged users.

The network-based attack vector means any authenticated user with network access to the iDRAC9 web interface can potentially exploit this vulnerability without requiring any user interaction. While the vulnerability does not allow write access or code execution, the ability to read arbitrary files can expose sensitive configuration information, authentication credentials, and other critical data stored on the iDRAC9 system.

Root Cause

The root cause of CVE-2020-5366 is insufficient input validation in the iDRAC9 web application. When processing certain requests that include file path parameters, the application fails to properly sanitize or validate user input to prevent directory traversal sequences. This allows attackers to manipulate input parameters to construct file paths that traverse outside the intended directory boundaries, gaining access to files anywhere on the file system that the web application process has permission to read.

Attack Vector

The attack is executed remotely over the network through the iDRAC9 web management interface. An attacker must first authenticate to the system, but only requires low-level privileges to exploit the vulnerability. The attack flow involves:

1. Authenticating to the iDRAC9 web interface with valid low-privilege credentials
2. Identifying vulnerable endpoints that accept file path parameters
3. Crafting malicious requests with path traversal sequences embedded in the input parameters
4. Submitting the crafted request to read arbitrary files from the system
5. Extracting sensitive information from the file contents returned in the response

No special tools or complex exploitation techniques are required beyond standard HTTP request manipulation. The vulnerability can be exploited using common web proxy tools or custom scripts.

Detection Methods for CVE-2020-5366

Indicators of Compromise

• Web server logs showing requests containing path traversal sequences such as ../, ..%2f, ..%5c, or other encoded variants
• Unusual file access patterns in iDRAC9 system logs from low-privileged user accounts
• HTTP requests to the iDRAC9 web interface with abnormally long URL parameters or query strings
• Evidence of sensitive system files being accessed through the web interface

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns
• Enable detailed logging on iDRAC9 systems and forward logs to a centralized SIEM for analysis
• Create detection rules to alert on suspicious file access patterns or path traversal attempts in HTTP request logs
• Monitor for anomalous behavior from authenticated iDRAC9 users, particularly access to files outside normal operational scope

Monitoring Recommendations

• Regularly audit iDRAC9 access logs for signs of exploitation attempts or unauthorized file access
• Implement network segmentation to isolate iDRAC9 management interfaces and monitor traffic for suspicious activity
• Deploy intrusion detection systems (IDS) with signatures for path traversal attack patterns
• Establish baseline behavior for iDRAC9 usage and alert on deviations that may indicate exploitation

How to Mitigate CVE-2020-5366

Immediate Actions Required

• Upgrade Dell EMC iDRAC9 firmware to version 4.20.20.20 or later immediately
• Review iDRAC9 access logs for evidence of prior exploitation attempts
• Restrict network access to iDRAC9 management interfaces to authorized management networks only
• Audit user accounts with access to iDRAC9 and enforce principle of least privilege

Patch Information

Dell has released iDRAC9 firmware version 4.20.20.20 which addresses this vulnerability. Administrators should download and apply the latest firmware update from the official Dell support channels. The security advisory is available at Dell Security Advisory DSA-2020-128 which provides detailed remediation guidance.

Workarounds

• Implement strict network access controls to limit iDRAC9 management interface access to trusted administrator workstations only
• Deploy a web application firewall or reverse proxy in front of iDRAC9 interfaces to filter malicious path traversal requests
• Disable or restrict access to any non-essential iDRAC9 web interface features until patching is complete
• Implement multi-factor authentication for iDRAC9 access where supported to reduce risk from compromised credentials

# Example network restriction using iptables
# Restrict iDRAC9 access (typically port 443) to management network only
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP