In recent years, Atlassian Confluence servers have become prime targets for cyber attackers, exploiting critical vulnerabilities to gain unauthorized access, deploy malware, and execute remote code. This article delves into the specifics of these attacks, the methodologies employed by threat actors, and the necessary measures organizations must adopt to safeguard their systems.
Understanding the Vulnerabilities
Atlassian Confluence, a widely used collaboration tool, has been plagued by several high-severity vulnerabilities:
1. CVE-2021-26084: An Object-Graph Navigation Language (OGNL) injection flaw allowing unauthenticated attackers to execute arbitrary code on affected systems. This vulnerability was patched on August 25, 2021, but exploitation attempts were observed shortly thereafter. ([rapid7.com](https://www.rapid7.com/blog/post/2021/09/02/active-exploitation-of-confluence-server-cve-2021-26084/?utm_source=openai))
2. CVE-2022-26134: A zero-day vulnerability reported by Volexity, enabling attackers to deploy webshells and gain full control over compromised servers. Atlassian released fixes by June 3, 2022. ([securityweek.com](https://www.securityweek.com/atlassian-confluence-servers-hacked-zero-day-vulnerability/?utm_source=openai))
3. CVE-2023-22527: A critical remote code execution (RCE) vulnerability affecting out-of-date versions of Confluence Data Center and Server. Within days of its disclosure, nearly 40,000 exploitation attempts were recorded. ([thehackernews.com](https://thehackernews.com/2024/01/40000-attacks-in-3-days-critical.html?utm_source=openai))
4. CVE-2023-22515: A privilege escalation vulnerability allowing unauthorized individuals to create administrator accounts on vulnerable Confluence servers. Microsoft observed exploitation by a Chinese APT group since September 14, 2023. ([hipaajournal.com](https://www.hipaajournal.com/atlassian-confluence-data-center-and-server-vulnerability-chinese-apt-actor/?utm_source=openai))
Attack Methodologies
Cyber attackers have employed sophisticated techniques to exploit these vulnerabilities:
– Initial Exploitation: Attackers exploit vulnerabilities like CVE-2023-22527 to execute arbitrary commands on target systems. For instance, they send crafted HTTP POST requests to specific endpoints, enabling the execution of malicious OGNL expressions. ([cyberpress.org](https://cyberpress.org/hackers-exploit-critical-confluence-server-flaw/?utm_source=openai))
– Deployment of Malware: Post-exploitation, attackers deploy various malware strains:
– Webshells: Tools like China Chopper and BEHINDER provide attackers with persistent access and control over compromised servers. ([securityweek.com](https://www.securityweek.com/atlassian-confluence-servers-hacked-zero-day-vulnerability/?utm_source=openai))
– Ransomware: Exploiting vulnerabilities such as CVE-2023-22527, attackers have deployed ransomware like LockBit Black, encrypting data and demanding ransoms. ([securityaid.co.uk](https://securityaid.co.uk/2025/02/24/hackers-exploited-confluence-server-vulnerability-to-deploy-lockbit-ransomware/?utm_source=openai))
– Cryptominers: Some attackers install cryptocurrency miners like XMRig, utilizing the victim’s resources for mining operations. ([sisainfosec.com](https://www.sisainfosec.com/sisa-news/atlassian-confluence-flaw-actively-exploited-to-install-cryptominers/?utm_source=openai))
– Persistence and Lateral Movement: To maintain access and expand their reach within networks, attackers:
– Install Remote Access Tools: Tools like AnyDesk are installed for persistent remote access. ([cyberpress.org](https://cyberpress.org/hackers-exploit-critical-confluence-server-flaw/?utm_source=openai))
– Create New Administrator Accounts: Attackers create accounts with elevated privileges to facilitate further exploitation. ([usa.kaspersky.com](https://usa.kaspersky.com/blog/confluence-data-center-server-vulnerability/29224/?utm_source=openai))
– Credential Theft: Tools like Mimikatz are used to extract credentials, enabling lateral movement across the network. ([cyberpress.org](https://cyberpress.org/hackers-exploit-critical-confluence-server-flaw/?utm_source=openai))
Case Studies
1. Jenkins Confluence Server Compromise: In September 2021, attackers exploited CVE-2021-26084 to gain access to Jenkins’ Confluence service, highlighting the critical need for timely patching. ([securityweek.com](https://www.securityweek.com/jenkins-says-confluence-service-compromised-using-recent-exploit/?utm_source=openai))
2. LockBit Ransomware Deployment: In February 2025, attackers exploited CVE-2023-22527 to deploy LockBit Black ransomware, encrypting data across enterprise networks within two hours of initial compromise. ([securityaid.co.uk](https://securityaid.co.uk/2025/02/24/hackers-exploited-confluence-server-vulnerability-to-deploy-lockbit-ransomware/?utm_source=openai))
3. Chinese APT Exploitation: Microsoft reported that a Chinese APT group exploited CVE-2023-22515 to create administrator accounts on vulnerable Confluence servers, emphasizing the role of nation-state actors in such attacks. ([hipaajournal.com](https://www.hipaajournal.com/atlassian-confluence-data-center-and-server-vulnerability-chinese-apt-actor/?utm_source=openai))
Mitigation Strategies
To protect against these threats, organizations should:
– Regularly Update Systems: Ensure all Confluence servers are updated to the latest versions to patch known vulnerabilities. ([usa.kaspersky.com](https://usa.kaspersky.com/blog/confluence-data-center-server-vulnerability/29224/?utm_source=openai))
– Monitor for Indicators of Compromise (IoCs): Regularly review logs for signs of exploitation, such as unexpected administrator accounts or unusual network traffic. ([usa.kaspersky.com](https://usa.kaspersky.com/blog/confluence-data-center-server-vulnerability/29224/?utm_source=openai))
– Implement Network Segmentation: Limit access to critical systems and services to reduce the potential impact of a breach.
– Deploy Endpoint Detection and Response (EDR) Solutions: Utilize EDR tools to detect and respond to suspicious activities promptly.
– Educate Employees: Conduct regular training sessions to raise awareness about phishing attacks and other common threat vectors.
Conclusion
The exploitation of Atlassian Confluence servers underscores the critical importance of proactive cybersecurity measures. By understanding the vulnerabilities, attack methodologies, and implementing robust mitigation strategies, organizations can significantly reduce their risk exposure and protect their digital assets from sophisticated cyber threats.
