CVE-2022-27907: Nexus Repository Manager SSRF Flaw

CVE-2022-27907 Overview

CVE-2022-27907 is a Server-Side Request Forgery (SSRF) vulnerability affecting Sonatype Nexus Repository Manager 3.x versions prior to 3.38.0. This vulnerability allows authenticated attackers to abuse the application's server-side functionality to make unauthorized requests to internal or external resources, potentially exposing sensitive internal services or data.

Critical Impact

Authenticated attackers can leverage this SSRF vulnerability to access internal network resources, potentially bypassing network segmentation and reaching services not intended to be publicly accessible.

Affected Products

• Sonatype Nexus Repository Manager 3.x versions before 3.38.0

Discovery Timeline

• 2022-03-30 - CVE-2022-27907 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-27907

Vulnerability Analysis

This SSRF vulnerability (CWE-918) in Sonatype Nexus Repository Manager allows an authenticated user to craft malicious requests that cause the server to make HTTP requests to arbitrary destinations. Because the requests originate from the server itself, they may bypass network security controls such as firewalls and access control lists that would otherwise block external access to internal resources.

The vulnerability requires low privileges to exploit and can be triggered remotely over the network without user interaction. While the direct impact is limited to information disclosure with no integrity or availability impact, SSRF vulnerabilities can serve as a stepping stone for more severe attacks, including accessing cloud metadata endpoints, internal APIs, or other sensitive services within the network perimeter.

Root Cause

The root cause of this vulnerability lies in improper validation of user-controlled input that specifies URLs or network destinations. The application fails to adequately restrict the destinations that the server can be directed to access, allowing attackers to specify arbitrary internal or external URLs. This is classified as CWE-918: Server-Side Request Forgery (SSRF).

Attack Vector

The attack vector is network-based, requiring the attacker to have authenticated access to the Nexus Repository Manager instance. Once authenticated, the attacker can manipulate request parameters to cause the server to initiate connections to attacker-specified destinations. This could include:

• Internal network services on private IP ranges (e.g., 10.x.x.x, 172.16.x.x, 192.168.x.x)
• Cloud provider metadata endpoints (e.g., 169.254.169.254)
• Internal microservices or APIs not exposed to the internet
• Localhost services running on the Nexus server itself

The vulnerability does not require complex attack chains and can be exploited with straightforward HTTP requests targeting the vulnerable functionality.

Detection Methods for CVE-2022-27907

Indicators of Compromise

• Unusual outbound connection attempts from the Nexus Repository Manager server to internal IP ranges or cloud metadata endpoints
• HTTP requests in application logs targeting internal network addresses or localhost
• Unexpected access to internal services that correlate with Nexus server activity
• Authentication events followed by suspicious network activity patterns

Detection Strategies

• Monitor Nexus Repository Manager application logs for requests containing internal IP addresses or known sensitive endpoints
• Implement network-level monitoring to detect outbound connections from the Nexus server to unexpected internal destinations
• Deploy SentinelOne's Singularity Platform to detect anomalous network behavior and SSRF exploitation patterns
• Review authentication logs to identify accounts potentially being used for exploitation attempts

Monitoring Recommendations

• Enable verbose logging on the Nexus Repository Manager to capture detailed request information
• Configure network segmentation monitoring to alert on traffic from the Nexus server to sensitive internal zones
• Implement egress filtering and monitoring at the network perimeter to detect unauthorized outbound connections
• Use SentinelOne's behavioral AI to identify exploitation attempts based on anomalous application behavior

How to Mitigate CVE-2022-27907

Immediate Actions Required

• Upgrade Sonatype Nexus Repository Manager to version 3.38.0 or later immediately
• Review access logs for signs of exploitation prior to patching
• Audit user accounts with access to the Nexus instance and remove unnecessary privileges
• Implement network segmentation to limit the potential impact of SSRF if exploitation occurs

Patch Information

Sonatype has addressed this vulnerability in Nexus Repository Manager version 3.38.0. Organizations should upgrade to this version or later to remediate the SSRF vulnerability. For detailed patch information and upgrade instructions, refer to the Sonatype Support Article.

Workarounds

• Restrict network access from the Nexus Repository Manager server to only required external destinations using firewall rules
• Implement egress filtering to block access to internal IP ranges and cloud metadata endpoints from the application server
• Use a web application firewall (WAF) to inspect and filter potentially malicious requests targeting SSRF patterns
• Apply the principle of least privilege to limit authenticated user permissions until patching is complete

# Example: Block cloud metadata endpoint access from Nexus server (Linux iptables)
iptables -A OUTPUT -d 169.254.169.254 -j DROP

# Example: Restrict outbound connections to internal networks
iptables -A OUTPUT -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -j DROP