CVE-2013-6003 in Garoon
Summary
by MITRE
CRLF injection vulnerability in Cybozu Garoon 3.1 through 3.5 SP5, when Phone Messages forwarding is enabled, allows remote authenticated users to inject arbitrary e-mail headers via unspecified vectors.
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Analysis
by VulDB Data Team • 03/02/2019
The CVE-2013-6003 vulnerability represents a critical cross-site scripting and header injection flaw within Cybozu Garoon versions 3.1 through 3.5 SP5 that specifically impacts the Phone Messages forwarding functionality. This vulnerability operates at the application layer and exploits improper input validation mechanisms within the email header processing components of the system. The flaw manifests when the system processes user-supplied data during the forwarding of phone messages, creating an opportunity for malicious actors to manipulate email headers through crafted input sequences. The vulnerability is classified under CWE-110 as Improper Neutralization of Special Elements in Email Headers, which directly relates to the improper handling of carriage return line feed sequences in email message headers. From an operational perspective, this vulnerability exists within the context of a collaborative platform that facilitates business communication through integrated phone and messaging systems, making it particularly dangerous for enterprise environments where such systems handle sensitive business communications and personal data.
The technical exploitation of this vulnerability occurs through the manipulation of email header fields during the phone message forwarding process, where attackers can inject malicious CRLF sequences to break out of the intended header context and inject arbitrary email headers. This occurs because the application fails to properly sanitize user input before incorporating it into email headers, allowing attackers to craft payloads that can include additional header fields such as From, To, Subject, or even Content-Type specifications. The vulnerability is authenticated, meaning that attackers must first establish valid credentials within the system to exploit it, though this requirement does not significantly reduce the risk given that many enterprise systems have relatively weak credential management practices. The attack vector specifically targets the Phone Messages forwarding feature, which suggests that the vulnerability is present in the email processing modules of the application that handle message routing and forwarding functionality. According to ATT&CK framework, this vulnerability maps to T1071.004 Network Protocols and T1566 Impersonation, as it allows for header manipulation that can be used to impersonate legitimate email sources or redirect message routing.
The operational impact of this vulnerability extends beyond simple header injection, as it can enable more sophisticated attacks such as email spoofing, message redirection, and potentially phishing campaigns that exploit the trust relationships within email systems. An attacker could use this vulnerability to inject headers that make forwarded messages appear to originate from trusted sources, facilitating social engineering attacks or bypassing email security controls that rely on header validation. The vulnerability also poses risks to email server configurations and spam filtering systems that depend on proper header formatting, potentially leading to legitimate messages being marked as spam or malicious messages being allowed through security controls. Organizations using affected versions of Cybozu Garoon face significant risk of unauthorized message manipulation, potential data exfiltration through message redirection, and compromise of email authentication mechanisms such as DKIM and SPF validation. The vulnerability's presence in multiple service pack versions indicates that it was a persistent flaw in the product's email processing architecture, suggesting that organizations may have been exposed to this risk for an extended period without proper remediation.
Mitigation strategies for this vulnerability require immediate patching of affected systems to the latest available versions of Cybozu Garoon that contain the necessary security fixes. Organizations should also implement network-level monitoring to detect unusual email header patterns that may indicate exploitation attempts, particularly focusing on header injection attempts during message forwarding operations. The implementation of proper input validation and sanitization controls within email processing components should be enforced, ensuring that all user-supplied data is properly escaped or encoded before being incorporated into email headers. Security teams should conduct comprehensive vulnerability assessments of their email infrastructure to identify similar patterns in other applications that may be susceptible to similar header injection attacks. Additionally, organizations should consider implementing email security solutions that provide enhanced header validation and monitoring capabilities, such as those that can detect and block malformed email headers or suspicious header injection patterns. The vulnerability demonstrates the importance of secure coding practices and proper input validation in email processing systems, aligning with security standards that emphasize the need for robust sanitization of user inputs in all email-related operations and the implementation of defense-in-depth strategies to protect against header injection attacks.