CVE-2015-5647 in Garoon
Summary
by MITRE
The RSS Reader component in Cybozu Garoon 3.x through 3.7.5 and 4.x through 4.0.3 allows remote authenticated users to execute arbitrary PHP code via unspecified vectors, aka CyVDB-866.
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Analysis
by VulDB Data Team • 01/31/2018
The vulnerability identified as CVE-2015-5647 represents a critical remote code execution flaw within the RSS Reader component of Cybozu Garoon software versions 3.x through 3.7.5 and 4.x through 4.0.3. This vulnerability classifies under CWE-94, which specifically addresses the execution of arbitrary code or commands, making it a severe security concern for organizations relying on this collaboration platform. The vulnerability affects a core component that processes RSS feeds, which are commonly used for aggregating content from various sources within enterprise environments.
The technical nature of this vulnerability stems from improper input validation and sanitization within the RSS Reader functionality. Attackers with authenticated access to the system can exploit this flaw by crafting malicious RSS feed content or manipulating existing feed data in ways that bypass security controls. The unspecified vectors suggest that the vulnerability could be triggered through multiple attack paths including but not limited to parameter manipulation, file inclusion attacks, or injection techniques that leverage the RSS parsing mechanism. This allows authenticated remote attackers to execute arbitrary PHP code on the target server with the privileges of the web application.
The operational impact of this vulnerability extends far beyond simple data compromise, as it provides attackers with complete control over the affected system. Once exploited, attackers can establish persistent access, escalate privileges, and potentially move laterally within the network to compromise additional systems. The vulnerability particularly affects enterprise collaboration environments where RSS feeds are commonly used for news aggregation, internal communications, and external content integration. Organizations using Cybozu Garoon for business-critical operations face significant risk of data breaches, system compromise, and potential regulatory violations if this vulnerability remains unpatched.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, specifically mapping it to techniques involving command and script injection, privilege escalation, and persistence mechanisms. The vulnerability aligns with ATT&CK technique T1059.007 for command and script injection and T1078 for valid accounts usage, as attackers require authenticated access to exploit it. Organizations should implement immediate mitigation strategies including applying the vendor-provided patches, implementing network segmentation to limit access to the affected components, and monitoring for suspicious RSS feed activity or unauthorized code execution attempts. The vulnerability demonstrates the critical importance of input validation in web applications and highlights the need for comprehensive security testing of all components, particularly those handling external data sources.