CVE-2022-26136: Atlassian Bamboo Auth Bypass Vulnerability

CVE-2022-26136 Overview

CVE-2022-26136 is a critical Servlet Filter bypass vulnerability affecting multiple Atlassian products. This flaw allows a remote, unauthenticated attacker to bypass Servlet Filters used by first and third-party applications. The actual impact varies depending on which filters are used by each app and how the filters are implemented, but confirmed consequences include authentication bypass and cross-site scripting (XSS) attacks.

The vulnerability exists across Atlassian's enterprise product suite, making it particularly concerning for organizations that rely on these tools for software development, collaboration, and IT service management. Because the vulnerability allows bypassing security filters without authentication, attackers can potentially gain unauthorized access to sensitive systems and data.

Critical Impact
Unauthenticated remote attackers can bypass Servlet Filters to achieve authentication bypass and cross-site scripting, potentially compromising enterprise collaboration and development infrastructure.

Affected Products

Atlassian Bamboo (versions before 8.0.9, from 8.1.0 before 8.1.8, and from 8.2.0 before 8.2.4)
Atlassian Bitbucket (versions before 7.6.16, from 7.7.0 before 7.17.8, from 7.18.0 before 7.19.5, from 7.20.0 before 7.20.2, from 7.21.0 before 7.21.2, and versions 8.0.0 and 8.1.0)
Atlassian Confluence Server and Data Center (versions before 7.4.17, from 7.5.0 before 7.13.7, from 7.14.0 before 7.14.3, from 7.15.0 before 7.15.2, from 7.16.0 before 7.16.4, from 7.17.0 before 7.17.4, and version 7.21.0)
Atlassian Crowd (versions before 4.3.8, from 4.4.0 before 4.4.2, and version 5.0.0)
Atlassian Fisheye and Crucible (versions before 4.8.10)
Atlassian Jira Server and Data Center (versions before 8.13.22, from 8.14.0 before 8.20.10, and from 8.21.0 before 8.22.4)
Atlassian Jira Service Management (versions before 4.13.22, from 4.14.0 before 4.20.10, and from 4.21.0 before 4.22.4)

Discovery Timeline

July 20, 2022 - CVE-2022-26136 published to NVD
November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-26136

Vulnerability Analysis

This vulnerability stems from improper handling of Servlet Filters within Atlassian's Java-based web applications. Servlet Filters are components that intercept HTTP requests and responses to perform security functions such as authentication, authorization, input validation, and output encoding. By bypassing these filters, attackers can circumvent security controls that would normally prevent unauthorized access or malicious input.

The vulnerability is classified under CWE-180 (Incorrect Behavior Order: Validate Before Canonicalize) and CWE-287 (Improper Authentication). The combination of these weaknesses indicates that the filter bypass occurs due to improper request processing order, allowing attackers to craft requests that evade security checks.

Atlassian has noted that while they have addressed the root cause, they have not exhaustively enumerated all potential consequences. This suggests the vulnerability could have additional exploitation scenarios beyond the confirmed authentication bypass and XSS attacks.

Root Cause

The root cause involves incorrect ordering or handling of Servlet Filter execution within the affected Atlassian products. When HTTP requests are processed, the security filters responsible for authentication and input sanitization can be bypassed through specially crafted requests. This allows malicious requests to reach application endpoints without proper security validation.

The vulnerability affects both first-party Atlassian filters and third-party filters installed via marketplace apps or custom development, amplifying the potential attack surface significantly.

Attack Vector

An attacker exploits this vulnerability by sending specially crafted HTTP requests to vulnerable Atlassian instances. The attack vector is network-based and requires no authentication or user interaction, making it highly exploitable.

The exploitation process typically involves:

Identifying a vulnerable Atlassian product exposed to the network
Crafting HTTP requests designed to bypass Servlet Filter processing
Exploiting the bypassed authentication to access restricted functionality
Alternatively, injecting malicious scripts that bypass XSS filters

Since the specific exploitation mechanism varies based on which filters are bypassed and how they're configured, the actual attack payloads differ across installations. The vulnerability affects the core filter processing mechanism, meaning any security control implemented via Servlet Filters could potentially be circumvented.

Detection Methods for CVE-2022-26136

Indicators of Compromise

Unusual authentication patterns or access to restricted endpoints without valid session tokens
Web server logs showing malformed or unusual HTTP requests targeting Atlassian application endpoints
Evidence of XSS payloads in application logs or user-submitted content
Unauthorized administrative actions or configuration changes in affected Atlassian products
Anomalous user account activity or creation of unauthorized accounts

Detection Strategies

Monitor web application firewall (WAF) logs for requests attempting to bypass authentication endpoints
Implement anomaly detection for HTTP request patterns that deviate from normal application behavior
Review Atlassian application access logs for authentication bypass attempts or unauthorized endpoint access
Deploy endpoint detection solutions to identify post-exploitation activity following successful authentication bypass

Monitoring Recommendations

Enable detailed access logging on all affected Atlassian products
Configure alerting for failed and successful authentication events from unexpected sources
Monitor for new user account creation or privilege escalation activities
Implement network traffic analysis to detect unusual communication patterns with Atlassian servers

How to Mitigate CVE-2022-26136

Immediate Actions Required

Identify all Atlassian products in your environment and determine their current versions
Restrict network access to Atlassian instances to trusted networks and users where possible
Review access logs for signs of exploitation attempts
Apply available security patches as the highest priority
Temporarily disable internet-facing access to vulnerable instances if patching cannot be performed immediately

Patch Information

Atlassian has released security updates that fix the root cause of this vulnerability. Organizations should upgrade to the following minimum versions:

Bamboo: 8.0.9, 8.1.8, or 8.2.4 (depending on your version branch)
Bitbucket: 7.6.16, 7.17.8, 7.19.5, 7.20.2, 7.21.2, or later releases after 8.1.0
Confluence: 7.4.17, 7.13.7, 7.14.3, 7.15.2, 7.16.4, 7.17.4, or later
Crowd: 4.3.8, 4.4.2, or later releases after 5.0.0
Fisheye/Crucible: 4.8.10 or later
Jira: 8.13.22, 8.20.10, or 8.22.4 (depending on your version branch)
Jira Service Management: 4.13.22, 4.20.10, or 4.22.4 (depending on your version branch)

Refer to the official Atlassian security advisories for your specific product: Atlassian Issue BAM-21795, Atlassian Issue BSERV-13370, Atlassian Issue CONFSERVER-79476, Atlassian Issue CWD-5815, Atlassian Issue FE-7410, Atlassian Issue CRUC-8541, Atlassian Issue JRASERVER-73897, and Atlassian Issue JSDSERVER-11863.

Workarounds

Implement network-level access controls to restrict access to Atlassian instances from untrusted networks
Deploy a web application firewall (WAF) with rules to detect and block filter bypass attempts
Enable additional authentication mechanisms such as multi-factor authentication where supported
Review and harden third-party app configurations that rely on Servlet Filters for security

bash

# Example: Restrict Atlassian instance access using iptables
# Allow access only from trusted corporate network
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP

# For Confluence/Jira behind a reverse proxy, configure access restrictions
# in your nginx or Apache configuration