CVE-2019-5977 in Garoon
Summary
by MITRE
Mail header injection vulnerability in Cybozu Garoon 4.0.0 to 4.10.2 may allow a remote authenticated attackers to alter mail header via the application 'E-Mail'.
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Analysis
by VulDB Data Team • 12/19/2023
The CVE-2019-5977 vulnerability represents a critical mail header injection flaw discovered in Cybozu Garoon versions 4.0.0 through 4.10.2. This vulnerability specifically affects the application's email functionality where authenticated attackers can manipulate mail headers through the E-Mail component. The flaw stems from insufficient input validation and sanitization of email header fields, creating a pathway for malicious actors to inject arbitrary header content into email messages. This type of vulnerability falls under the category of CWE-1107, which specifically addresses improper neutralization of special elements used in email headers, making it particularly dangerous in email processing environments where header manipulation can lead to various security implications including spam relay, phishing attacks, and email spoofing.
The technical implementation of this vulnerability occurs when the application fails to properly validate and sanitize user-supplied input before incorporating it into email headers. Attackers can exploit this by crafting malicious email content that includes header injection sequences such as carriage return and line feed characters, which when processed by the vulnerable application, result in the insertion of additional headers into the email message. This allows attackers to manipulate email routing, modify sender information, or inject malicious content that could bypass security measures. The vulnerability is particularly concerning because it requires only authenticated access to the application, meaning that internal users with legitimate email privileges can exploit this flaw to compromise email integrity and potentially gain unauthorized access to sensitive information flows.
The operational impact of CVE-2019-5977 extends beyond simple header manipulation, as it can enable sophisticated attack vectors that leverage the compromised email functionality. Attackers can use this vulnerability to create email messages that appear to originate from trusted sources, facilitating social engineering attacks and phishing campaigns that bypass traditional email security controls. The vulnerability also poses risks to email server configurations and can be exploited to relay spam or malicious content through the compromised system, potentially damaging the organization's reputation and violating email deliverability standards. Organizations using vulnerable versions of Cybozu Garoon face increased risk of email-based attacks that could compromise sensitive communications and data integrity, with potential implications for compliance with email security regulations and standards.
Organizations should immediately implement mitigations including applying the vendor-provided security patches and updates to resolve the vulnerability. Network segmentation and email monitoring systems should be enhanced to detect unusual header patterns and potential injection attempts. Access controls should be reviewed to ensure that only authorized personnel have access to email functionality, and additional logging should be implemented to track email header modifications. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, aligning with ATT&CK technique T1190 for exploit public-facing application and T1078 for valid accounts. Security teams should also consider implementing email header validation policies and regular security assessments to identify similar vulnerabilities in other email processing systems and applications within their environment.