CVE-2023-22527: Critical Unauthenticated RCE in Atlassian Confluence Data Center and Server
Atlassian Confluence Data Center and Server contain an unauthenticated OGNL template injection vulnerability that can lead to remote code execution.
FREQUENTLY ASKED
What is CVE-2023-22527 and why does it matter?
CVE-2023-22527 is a critical unauthenticated template injection vulnerability in Atlassian Confluence Data Center and Server. It carries a CVSS score of 10.0, the highest possible severity, because it allows remote attackers to execute arbitrary code without needing a valid account. This is a primary target for ransomware groups and automated exploit kits, making immediate remediation essential.
Which versions of Confluence are affected by this vulnerability?
The vulnerability affects older versions of Confluence Data Center and Server, specifically those before version 8.0.0 and various versions within the 8.x branch including 8.0.x, 8.1.x, 8.2.x, 8.3.x, 8.4.x, and specific sub-versions of 8.5.x. Recent versions that include security updates from the January Security Bulletin are mitigated, but instances running outdated builds remain highly vulnerable.
Has a patch been released for CVE-2023-22527?
Yes, Atlassian has released updates to address this vulnerability. Mitigation is achieved by upgrading to the latest supported versions of Confluence Data Center or Server. For users on the Long Term Support (LTS) branch, versions such as 8.5.4 or later provide protection. It is recommended to consult the Atlassian security advisory for the specific fixed version relative to your current deployment.
What is the remediation deadline and what does it mean for compliance?
The remediation deadline is set for 2024-02-14. This deadline is critical for organizations following federal compliance standards, such as CISA's Binding Operational Directive 22-01. Failing to patch by this date indicates a significant risk posture and may violate internal or regulatory compliance mandates regarding the management of known exploited vulnerabilities.
How can I check if my Confluence instance is affected?
Administrators should check the version number of their Confluence Data Center or Server installation by navigating to the 'Administration' console and viewing the 'System Information' page. If the version number is within the affected ranges (e.g., older than 8.0.0 or between 8.0.x and 8.5.3), the instance is likely vulnerable and requires an immediate update to a mitigated version.
CVE-2023-22527 is a critical unauthenticated Remote Code Execution (RCE) vulnerability in Atlassian Confluence Data Center and Server, carrying a CVSS score of 10.0. Due to its active exploitation and known use by ransomware actors, administrators must apply patches by the February 14, 2024, deadline to prevent total system compromise.
CWE-74 (Improper Neutralization of Special Elements)
Date Disclosed
2024-01-24
Remediation Deadline
2024-02-14
SSVC Exploitation Status
Active
Known Ransomware Use
Yes
EPSS Score & Percentile
0.94354 (100th Percentile)
Patch Available
Yes
Technical Deep Dive: CWE-74 and OGNL Injection
CVE-2023-22527 is categorized under CWE-74, which refers to the improper neutralization of special elements in output used by a downstream component, specifically leading to Template Injection. In the context of Atlassian Confluence, this vulnerability manifests through the misuse of the Object-Graph Navigation Language (OGNL). OGNL is an expression language used for getting and setting properties of Java objects and for executing methods of those objects.
When a web application allows user-supplied input to be interpreted as an OGNL expression without proper sanitization, it creates a direct path to Remote Code Execution (RCE). In this specific case, the vulnerability exists in older versions of the Confluence template engine. An unauthenticated attacker can craft a malicious HTTP request containing OGNL syntax that the server incorrectly processes. Because the expression is executed within the context of the server process, the attacker can bypass security sandboxes to invoke underlying Java classes, such as java.lang.Runtime, to execute arbitrary system commands.
The Attack Chain and Blast Radius
The attack surface for CVE-2023-22527 is exceptionally broad because it requires no prior authentication. This means any Confluence instance exposed to the public internet is at risk. The "blast radius" is total system compromise; since the attacker can execute code with the privileges of the user running the Confluence service, they can effectively access all data stored in the wiki, pivot to connected databases, or move laterally across the internal network.
Comparatively, this vulnerability echoes previous Confluence issues like CVE-2022-26134. However, CVE-2023-22527 is particularly dangerous due to its high EPSS score (0.94+), which indicates a nearly 100% certainty of ongoing exploitation in the wild. The SSVC status of "active" and "automatable" further emphasizes that botnets and ransomware operators are actively scanning for these specific OGNL injection points.
Who Is Affected: Impacted Versions and Compliance
This vulnerability impacts a wide range of older Confluence Data Center and Server versions. Organizations running versions prior to 8.0.0 are universally affected. Within the 8.x release stream, specific versions including 8.0.x through 8.4.x and early Long Term Support (LTS) releases like 8.5.0 through 8.5.3 are vulnerable.
CISA BOD 22-01 Compliance
For organizations operating within the United States federal civilian executive branch, or those following CISA guidelines, this CVE is a high-priority entry in the Known Exploited Vulnerabilities (KEV) catalog. The remediation deadline of 2024-02-14 is a mandatory cutoff. Failure to apply the vendor-provided patches by this date constitutes a direct violation of Binding Operational Directive (BOD) 22-01. Private sector organizations are strongly encouraged to adopt this same timeline to mitigate the proven risk of ransomware deployment associated with this flaw.
Official Remediation Steps
Atlassian has confirmed that current supported versions are not affected if they have been updated according to the January Security Bulletin. To secure your environment, follow these steps:
Identify Your Version: Log into your Confluence instance and navigate to Administration > System Information to verify your current build number.
Backup Data: Before performing any upgrade, ensure a full backup of the Confluence home directory and the underlying database is completed.
Upgrade to Fixed Versions:
For customers on the 8.5.x LTS branch, upgrade to version 8.5.4 or higher.
For customers on the latest feature releases, upgrade to version 8.7.2 or higher.
Users on versions older than 8.0.0 must move to a supported 8.x release immediately.
Verify Mitigation: After the upgrade, confirm the version number and monitor server logs for any unusual OGNL-related stack traces or unauthorized access attempts.
Reference Official Documentation: Detailed upgrade instructions and version-specific notes are available via the Atlassian Patch URL.
Security Best Practices for Atlassian Environments
Beyond patching CVE-2023-22527, organizations should implement defense-in-depth strategies to protect against future injection-based attacks:
Network Segmentation: Isolate Confluence servers from the public internet using a VPN or Zero Trust Network Access (ZTNA) solution. If public access is required, restrict traffic to known IP ranges.
WAF Implementation: Deploy a Web Application Firewall (WAF) with rules specifically designed to detect and block OGNL expression patterns (e.g., looking for ${...} or %{...} syntax in URI parameters and headers).
Principle of Least Privilege: Run the Confluence service under a dedicated low-privilege service account. Avoid running the application as 'root' or 'Administrator' to limit the impact of an RCE.
Enhanced Monitoring: Implement File Integrity Monitoring (FIM) and log aggregation to detect the creation of web shells or unusual child processes (like cmd.exe or /bin/sh) initiated by the Java process.
Regular Patch Cycles: Transition to Long Term Support (LTS) versions of Atlassian products to receive stable security backports while minimizing functional disruptions.
Audit unauthenticated access: Regularly review which Confluence spaces or endpoints allow unauthenticated (anonymous) access and disable it wherever it is not strictly necessary for business operations.