CVE-2023-22512: Confluence Data Center DoS Vulnerability

CVE-2023-22512 Overview

CVE-2023-22512 is a high-severity Denial of Service (DoS) vulnerability affecting Atlassian Confluence Data Center and Server. This vulnerability was introduced in version 5.6.0 and allows an unauthenticated attacker to disrupt the availability of Confluence instances connected to a network. The attack can temporarily or indefinitely make the service unavailable to its intended users without requiring any user interaction.

This vulnerability is particularly concerning for organizations relying on Confluence for documentation and collaboration, as it can be exploited remotely by unauthenticated attackers to cause service outages. The vulnerability has no impact on data confidentiality or integrity but poses a significant threat to service availability.

Critical Impact

Unauthenticated attackers can cause complete service disruption to Confluence instances, potentially affecting organizational productivity and collaboration workflows.

Affected Products

• Atlassian Confluence Data Center versions from 5.6.0 to below 7.19.14
• Atlassian Confluence Server versions from 5.6.0 to below 7.19.14
• Atlassian Confluence Data Center and Server versions 8.0.x to below 8.5.1

Discovery Timeline

• 2024-01-16 - CVE-2023-22512 published to NVD
• 2025-05-12 - Last updated in NVD database

Technical Details for CVE-2023-22512

Vulnerability Analysis

This Denial of Service vulnerability allows unauthenticated remote attackers to exhaust resources on vulnerable Confluence instances. The attack can be launched over the network without requiring any privileges or user interaction, making it particularly dangerous for internet-facing Confluence deployments.

The vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption), indicating that the underlying issue involves improper handling of resource allocation or limits. When exploited, attackers can cause the Confluence service to become unresponsive or completely unavailable to legitimate users.

Organizations running affected versions of Confluence Data Center or Server should treat this vulnerability with urgency, especially if their instances are accessible from untrusted networks. The vulnerability was discovered and reported through Atlassian's Bug Bounty program.

Root Cause

The vulnerability stems from improper resource management within Confluence Data Center and Server. Based on the CWE-400 classification, the application fails to adequately limit or control the consumption of system resources when processing certain requests. This lack of proper resource controls allows malicious actors to trigger resource exhaustion conditions that render the service unavailable.

Attack Vector

The attack vector for CVE-2023-22512 is network-based, requiring no authentication or user interaction. An attacker with network access to a vulnerable Confluence instance can send specially crafted requests that trigger the resource exhaustion condition. The attack complexity is low, meaning that exploitation does not require specialized conditions or sophisticated techniques.

The vulnerability affects Confluence instances that are accessible over the network, making internet-facing deployments particularly at risk. However, internal deployments can also be targeted by attackers who have gained access to the corporate network.

Detection Methods for CVE-2023-22512

Indicators of Compromise

• Unusual spikes in resource utilization (CPU, memory, network connections) on Confluence servers
• Confluence service becoming unresponsive or restarting frequently without scheduled maintenance
• Abnormal patterns of requests from single or multiple IP addresses targeting Confluence endpoints
• Error logs indicating resource exhaustion, connection timeouts, or out-of-memory conditions

Detection Strategies

• Monitor Confluence application and server logs for signs of resource exhaustion or service degradation
• Implement network-level monitoring to detect unusual traffic patterns targeting Confluence instances
• Deploy SentinelOne Singularity to detect anomalous process behavior and resource consumption patterns on Confluence hosts
• Configure alerting for Confluence service availability and response time degradation

Monitoring Recommendations

• Enable verbose logging on Confluence instances to capture detailed request information
• Set up automated health checks to detect service availability issues promptly
• Monitor system resources (CPU, memory, disk I/O, network connections) on Confluence servers with baseline thresholds
• Implement network traffic analysis to identify potential DoS attack patterns

How to Mitigate CVE-2023-22512

Immediate Actions Required

• Identify all Confluence Data Center and Server instances in your environment and determine their version numbers
• Prioritize patching internet-facing Confluence instances as they are at highest risk
• Consider temporarily restricting network access to Confluence instances until patching is complete
• Review and strengthen rate limiting and connection throttling configurations

Patch Information

Atlassian recommends upgrading to the latest version of Confluence Data Center and Server. If immediate upgrade to the latest version is not possible, the following minimum versions address this vulnerability:

• Confluence Data Center and Server 7.19.x: Upgrade to version 7.19.14 or later
• Confluence Data Center and Server 8.5.x: Upgrade to version 8.5.1 or later
• Confluence Data Center and Server 8.6 or above: No action required, these versions are already patched

For detailed patch information and download links, refer to the Atlassian Confluence Security Advisory and the JIRA issue CONFSERVER-91258.

Workarounds

• Implement network-level rate limiting to restrict the number of requests from individual IP addresses
• Place Confluence behind a web application firewall (WAF) with DoS protection capabilities
• Restrict access to Confluence to trusted IP ranges using firewall rules or reverse proxy configurations
• Monitor and scale infrastructure resources to handle potential attack attempts while patching is planned

# Example: Restrict Confluence access using iptables (adjust as needed)
# Limit new connections to Confluence port (default 8090) from external sources
iptables -A INPUT -p tcp --dport 8090 -m connlimit --connlimit-above 50 -j DROP
iptables -A INPUT -p tcp --dport 8090 -m state --state NEW -m limit --limit 25/minute --limit-burst 100 -j ACCEPT