CVE-2008-4677 in netrw
Summary
by MITRE
autoload/netrw.vim (aka the Netrw Plugin) 109, 131, and other versions before 133k for Vim 7.1.266, other 7.1 versions, and 7.2 stores credentials for an FTP session, and sends those credentials when attempting to establish subsequent FTP sessions to servers on different hosts, which allows remote FTP servers to obtain sensitive information in opportunistic circumstances by logging usernames and passwords. NOTE: the upstream vendor disputes a vector involving different ports on the same host, stating "I m assuming that they re using the same id and password on that unchanged hostname, deliberately."
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Analysis
by VulDB Data Team • 08/30/2019
The vulnerability identified as CVE-2008-4677 resides within the netrw plugin of Vim text editor, specifically affecting versions prior to 133k. This issue represents a credential exposure flaw that operates through the automatic loading mechanism of the netrw plugin, which handles network file operations including ftp connections. The vulnerability stems from the plugin's improper handling of authentication credentials during ftp session establishment, creating a persistent security risk that extends beyond the initial connection context.
The technical flaw manifests when the netrw plugin stores ftp credentials in memory or configuration files during an initial ftp session. These stored credentials are subsequently reused when attempting to establish new ftp connections to different hosts, creating an unintentional credential sharing mechanism. The vulnerability operates through the autoload functionality of vim where plugins are automatically loaded when needed, making the exploitation occur without explicit user interaction or awareness. This behavior violates the principle of least privilege and creates an attack surface where remote ftp servers can potentially intercept or capture these stored credentials through opportunistic network monitoring or malicious server configurations.
The operational impact of this vulnerability extends beyond simple credential theft to encompass potential unauthorized access to systems and data. When users establish ftp connections through vim's netrw plugin, their credentials become persistently available for reuse across different ftp servers, creating a scenario where a single compromised ftp server could capture credentials intended for other systems. This vulnerability particularly affects environments where users frequently connect to multiple ftp servers or where ftp connections are established automatically as part of routine operations. The security implications include potential privilege escalation, unauthorized data access, and the possibility of credential reuse across different network environments.
The vulnerability aligns with CWE-255 Credentials Management Issues and CWE-312 Cleartext Storage of Sensitive Information, demonstrating poor handling of authentication data and insecure credential storage practices. From an ATT&CK framework perspective, this vulnerability maps to T1552 Credential Access and T1071.1001 Application Layer Protocol, as it involves the exploitation of application layer protocols to capture authentication information. The upstream vendor's position regarding different ports on the same host suggests that the vulnerability is primarily concerned with cross-host credential reuse rather than internal port manipulation, though the fundamental flaw remains in the credential persistence mechanism.
Mitigation strategies should focus on immediate patching to versions 133k or later where the credential handling has been corrected. Users should disable the netrw plugin if ftp functionality is not required, or configure vim to use secure credential management mechanisms. Network administrators should monitor for suspicious ftp traffic patterns that might indicate credential harvesting attempts. Additionally, implementing network segmentation and credential rotation policies can help reduce the impact of credential exposure. The vulnerability underscores the importance of proper credential lifecycle management and secure plugin architecture in text editors and development environments.