CVE-2020-5377: Dell EMC OMSA Path Traversal Vulnerability

CVE-2020-5377 Overview

Dell EMC OpenManage Server Administrator (OMSA) versions 9.4 and prior contain multiple path traversal vulnerabilities. An unauthenticated remote attacker could potentially exploit these vulnerabilities by sending a crafted Web API request containing directory traversal character sequences to gain file system access on the compromised management station. This vulnerability poses significant risks to enterprise environments where OMSA is deployed for server management operations.

Critical Impact

Unauthenticated attackers can read arbitrary files from the file system, potentially exposing sensitive configuration data, credentials, and system information without any authentication requirements.

Affected Products

• Dell EMC OpenManage Server Administrator versions 9.4 and prior
• All deployments of OMSA with the Web API interface exposed to network access
• Enterprise server management environments utilizing Dell OMSA for remote administration

Discovery Timeline

• July 28, 2020 - CVE-2020-5377 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-5377

Vulnerability Analysis

This path traversal vulnerability (CWE-22) in Dell EMC OpenManage Server Administrator allows unauthenticated remote attackers to access files outside the intended directory structure. The vulnerability exists in the Web API component of OMSA, which fails to properly sanitize user-supplied input containing directory traversal sequences such as ../ or ..\. When exploited, attackers can navigate outside the web root directory and read arbitrary files from the underlying operating system.

The attack requires no authentication or user interaction, making it particularly dangerous in environments where OMSA is accessible over the network. Successful exploitation enables attackers to read sensitive files including configuration files, password hashes, and other critical system data.

Root Cause

The root cause of CVE-2020-5377 is improper input validation in the Web API request handling mechanism. The application fails to adequately sanitize file path parameters before processing file read operations. When the application constructs file paths using user-controlled input, it does not properly filter or canonicalize directory traversal sequences. This allows attackers to break out of the intended directory scope and access files anywhere on the file system that the OMSA service account has read permissions to access.

Attack Vector

The attack is conducted remotely over the network against the OMSA Web API interface. An attacker sends specially crafted HTTP requests containing path traversal sequences (such as ../../../etc/passwd or similar patterns) to the vulnerable Web API endpoints. The server processes these requests without proper validation, allowing the attacker to traverse directories and read files from arbitrary locations on the server's file system.

The exploitation does not require authentication, credentials, or any prior access to the target system. The attacker only needs network access to the OMSA web interface, typically running on ports 1311 (HTTPS) or similar configurations.

The vulnerability mechanism involves crafting malicious Web API requests that include directory traversal sequences within file path parameters. When the OMSA application processes these requests, it fails to normalize or validate the path, allowing attackers to escape the intended directory and access sensitive files. Technical details and exploitation methodology are documented in the Packet Storm File Read Exploit.

Detection Methods for CVE-2020-5377

Indicators of Compromise

• Web server logs containing requests with path traversal sequences such as ../, ..%2f, ..%5c, or URL-encoded variants
• Unusual access patterns to the OMSA Web API from external or unexpected IP addresses
• HTTP requests targeting known sensitive file paths combined with traversal sequences (e.g., requests attempting to access /etc/passwd, /etc/shadow, or Windows system files)
• Increased read operations on system files outside the OMSA application directory

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns
• Deploy network intrusion detection systems (IDS) with signatures for directory traversal attacks targeting OMSA endpoints
• Monitor OMSA service logs for unusual file access requests or error messages indicating path manipulation attempts
• Utilize endpoint detection and response (EDR) solutions to monitor file system access patterns from the OMSA process

Monitoring Recommendations

• Enable detailed logging for all OMSA Web API requests and review logs regularly for suspicious patterns
• Configure alerting for any requests containing encoded or raw directory traversal sequences
• Monitor network traffic to OMSA ports (typically 1311) for anomalous request patterns
• Implement file integrity monitoring on critical system files to detect unauthorized access attempts

How to Mitigate CVE-2020-5377

Immediate Actions Required

• Upgrade Dell EMC OpenManage Server Administrator to a version newer than 9.4 that contains the security fix
• Restrict network access to OMSA interfaces using firewall rules, limiting access to trusted management networks only
• If immediate patching is not possible, consider temporarily disabling the OMSA web interface until patches can be applied
• Review access logs for any evidence of exploitation attempts

Patch Information

Dell has released a security update addressing this vulnerability. Organizations should upgrade to OMSA version 9.5 or later to remediate CVE-2020-5377. For detailed patch information and download links, refer to the Dell Security Advisory DSA-2020-172.

Workarounds

• Implement strict network segmentation to isolate OMSA management interfaces from untrusted networks
• Deploy a reverse proxy or web application firewall (WAF) in front of OMSA to filter malicious requests containing path traversal sequences
• Configure host-based firewall rules to restrict OMSA access to specific management IP addresses
• Disable the OMSA web interface if remote web-based management is not required

# Example: Restrict OMSA access to trusted management network using iptables
iptables -A INPUT -p tcp --dport 1311 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 1311 -j DROP