CVE-2020-36289: Atlassian Jira Data Center Disclosure Flaw

CVE-2020-36289 Overview

CVE-2020-36289 is an Information Disclosure vulnerability affecting Atlassian Jira Server and Data Center that allows unauthenticated attackers to enumerate valid usernames through the QueryComponentRendererValue!Default.jspa endpoint. This vulnerability stems from improper authorization controls (CWE-863) that expose user information to unauthorized parties.

The vulnerability enables attackers to systematically discover valid user accounts without requiring any authentication, which can serve as reconnaissance for subsequent attacks such as credential stuffing, phishing campaigns, or brute force attempts against known valid accounts.

Critical Impact

Unauthenticated user enumeration enables attackers to identify valid accounts for targeted attacks, significantly increasing the risk of account compromise and unauthorized access to sensitive project data.

Affected Products

• Atlassian Jira Server versions before 8.5.13
• Atlassian Jira Server and Data Center versions from 8.6.0 before 8.13.5
• Atlassian Jira Server and Data Center versions from 8.14.0 before 8.15.1

Discovery Timeline

• May 12, 2021 - CVE-2020-36289 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-36289

Vulnerability Analysis

This Information Disclosure vulnerability exists in the QueryComponentRendererValue!Default.jspa endpoint within Atlassian Jira Server and Data Center. The endpoint fails to properly validate whether the requesting user is authenticated before returning user-related information. As a result, unauthenticated remote attackers can query this endpoint to determine whether specific usernames exist within the Jira instance.

The root issue lies in missing authorization checks (CWE-863: Incorrect Authorization) that should prevent anonymous access to user enumeration functionality. When exploited, the endpoint responds differently based on whether a queried username exists, allowing attackers to systematically enumerate valid user accounts.

Root Cause

The vulnerability is caused by incorrect authorization implementation in the QueryComponentRendererValue!Default.jspa endpoint. The endpoint lacks proper authentication and authorization validation, allowing unauthenticated users to access functionality that should be restricted to authenticated sessions only. This design flaw exposes user existence information through response variations.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by sending crafted HTTP requests to the vulnerable endpoint from any network location that can reach the Jira instance. The attack complexity is low, making it easily exploitable by attackers with minimal technical skill.

Attackers can automate enumeration by scripting requests to the QueryComponentRendererValue!Default.jspa endpoint with different username values and analyzing the responses to determine which accounts exist in the system. This enumerated data can then be used to target valid accounts in subsequent attacks.

Detection Methods for CVE-2020-36289

Indicators of Compromise

• Unusual volume of requests to /secure/QueryComponentRendererValue!Default.jspa endpoint
• Sequential or patterned requests containing different username parameters
• Requests to the vulnerable endpoint from external IP addresses
• Access log entries showing repeated queries to the endpoint without valid session cookies

Detection Strategies

• Monitor web application firewall (WAF) logs for suspicious patterns targeting the QueryComponentRendererValue!Default.jspa endpoint
• Implement rate limiting on authentication-related endpoints to detect enumeration attempts
• Configure alerting for high-frequency requests from single IP addresses to Jira endpoints
• Review Jira access logs for anonymous requests to sensitive endpoints

Monitoring Recommendations

• Enable detailed access logging for the Jira application and retain logs for security analysis
• Deploy network-based intrusion detection systems to identify user enumeration patterns
• Implement SIEM rules to correlate multiple failed or suspicious requests targeting user-related endpoints
• Consider deploying SentinelOne Singularity Platform for real-time endpoint and network visibility

How to Mitigate CVE-2020-36289

Immediate Actions Required

• Upgrade Jira Server to version 8.5.13 or later for the 8.5.x branch
• Upgrade Jira Server and Data Center to version 8.13.5 or later for the 8.6.x through 8.13.x branches
• Upgrade Jira Server and Data Center to version 8.15.1 or later for the 8.14.x through 8.15.x branches
• Review access logs for evidence of prior exploitation attempts

Patch Information

Atlassian has released security patches addressing this vulnerability. Detailed patch information and upgrade instructions are available in the Atlassian Jira Issue JRASERVER-71559. Organizations should prioritize upgrading to the fixed versions as this vulnerability has a high EPSS score of 92%, indicating significant likelihood of exploitation in the wild.

Workarounds

• Restrict external network access to the Jira instance using firewall rules until patching is complete
• Implement a reverse proxy or WAF to block unauthenticated requests to the vulnerable endpoint
• Enable IP-based access controls to limit access to trusted networks
• Monitor for exploitation attempts while preparing for the upgrade

# Example: Block access to vulnerable endpoint using Apache mod_rewrite
# Add to Jira's Apache configuration
<Location "/secure/QueryComponentRendererValue!Default.jspa">
    Order deny,allow
    Deny from all
    Allow from 10.0.0.0/8
    Allow from 192.168.0.0/16
</Location>