CVE-2015-4771 in MySQL Server
Summary
by MITRE
Unspecified vulnerability in Oracle MySQL Server 5.6.24 and earlier allows remote authenticated users to affect availability via vectors related to RBR.
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Analysis
by VulDB Data Team • 06/03/2022
The vulnerability identified as CVE-2015-4771 resides within Oracle MySQL Server versions 5.6.24 and earlier, representing a significant threat to database availability and system stability. This unspecified flaw specifically impacts the replication functionality of the database server, where remote authenticated users can exploit the vulnerability to disrupt service availability. The issue is particularly concerning as it leverages the Row-Based Replication (RBR) mechanism, which is a critical component of MySQL's data synchronization capabilities. When exploited, this vulnerability allows attackers to cause denial of service conditions that can severely impact database operations and overall system performance. The vulnerability's classification as remote authenticated indicates that exploitation does not require physical access to the system, making it particularly dangerous in networked environments where database servers are exposed to external networks.
The technical nature of this vulnerability is rooted in the handling of replication events within MySQL's architecture, specifically when processing row-based replication operations. The flaw manifests during the processing of replication events that occur when data changes are propagated from a master server to one or more slave servers in a replication topology. This type of vulnerability typically involves improper validation or handling of replication data that can lead to resource exhaustion, memory corruption, or other conditions that cause the replication process to fail or the server to become unresponsive. The RBR mechanism, which tracks individual row changes rather than statement-based changes, creates specific attack vectors that can be manipulated to cause system instability. The vulnerability's impact on availability suggests that successful exploitation can result in complete service disruption, requiring manual intervention to restore normal operations.
The operational impact of CVE-2015-4771 extends beyond simple service interruption to potentially compromise entire database infrastructures that rely on replication for high availability and disaster recovery. Organizations using MySQL in production environments where replication is configured face significant risk of extended downtime and data inconsistency issues. The vulnerability affects not only the immediate database server but also the entire replication chain, potentially causing cascading failures across multiple servers. System administrators must consider the broader implications for business continuity, as database unavailability can impact numerous applications that depend on the database for their operations. The authentication requirement for exploitation means that attackers must already have valid credentials, but this does not significantly reduce the risk given that credential compromise is a common attack vector in database environments. The vulnerability's presence in MySQL 5.6.24 and earlier versions indicates that organizations with legacy deployments face particular exposure, as these versions may not receive security updates or may not be actively maintained.
Mitigation strategies for CVE-2015-4771 primarily focus on upgrading to patched versions of Oracle MySQL Server, which would address the underlying replication handling issues that lead to availability problems. Organizations should prioritize patch management processes to ensure all MySQL installations are updated to versions that contain the necessary security fixes. Additionally, implementing network segmentation and access controls can help limit the potential impact by restricting access to database servers to only authorized users and systems. Monitoring and logging configurations should be enhanced to detect unusual replication behavior or patterns that might indicate exploitation attempts. The vulnerability's relationship to RBR operations suggests that administrators might consider alternative replication strategies or implement additional safeguards around replication processes. Security teams should also conduct regular vulnerability assessments to identify other potential weaknesses in their database environments and ensure that proper access controls are in place to prevent unauthorized users from gaining the authentication credentials necessary for exploitation. This vulnerability aligns with common attack patterns documented in the attack framework, particularly those targeting database availability through replication mechanisms, and represents a classic example of how replication features can become attack vectors when not properly secured.