CVE-2017-7983 in Joomla
Summary
by MITRE
In Joomla! 1.5.0 through 3.6.5 (fixed in 3.7.0), mail sent using the JMail API leaked the used PHPMailer version in the mail headers.
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Analysis
by VulDB Data Team • 12/21/2020
The vulnerability identified as CVE-2017-7983 represents a significant information disclosure flaw within the Joomla! content management system that affected versions from 1.5.0 through 3.6.5. This issue emerged due to improper handling of email headers when utilizing the JMail API component, which is responsible for email functionality within the Joomla framework. The flaw allowed attackers to determine the specific PHPMailer version being used by the Joomla installation through examination of email headers, creating a potential attack vector that could be leveraged in subsequent exploitation attempts.
The technical root cause of this vulnerability stems from the JMail API's implementation where it appended PHPMailer version information directly into the email headers without proper sanitization or obfuscation. This behavior violates security best practices for information disclosure prevention and creates a scenario where attackers can gather intelligence about the underlying infrastructure. The vulnerability manifests when Joomla! sends emails through the JMail API, with the PHPMailer version number appearing in the Received header or other email metadata fields, making it accessible to anyone who intercepts or analyzes the email communications.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with critical version information that can be used for further exploitation. When combined with other reconnaissance data, the specific PHPMailer version can help attackers identify known vulnerabilities within that particular version, potentially enabling them to craft targeted attacks against the system. This information leakage creates a foundation for more sophisticated attacks that might exploit other vulnerabilities present in the specific PHPMailer version, making the initial information disclosure a critical first step in a broader attack strategy. The vulnerability affects all Joomla! installations using the JMail API for email functionality, regardless of the specific Joomla version within the affected range.
Security mitigations for CVE-2017-7983 primarily involve upgrading to Joomla! version 3.7.0 or later, which includes the necessary patches to prevent PHPMailer version leakage in email headers. Organizations should also implement network monitoring to detect unusual email traffic patterns and consider implementing email header filtering mechanisms to prevent information disclosure. This vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and can be categorized under ATT&CK technique T1082, Information Discovery, as it enables adversaries to gather system information through email header analysis. Regular security audits and vulnerability assessments should be conducted to ensure that email components do not inadvertently expose sensitive version information, as this type of information disclosure can significantly weaken an organization's security posture and provide attackers with valuable intelligence for targeted attacks.