CVE-2015-9231 in iTerm2
Summary
by MITRE
iTerm2 3.x before 3.1.1 allows remote attackers to discover passwords by reading DNS queries. A new (default) feature was added to iTerm2 version 3.0.0 (and unreleased 2.9.x versions such as 2.9.20150717) that resulted in a potential information disclosure. In an attempt to see whether the text under the cursor (or selected text) was a URL, the text would be sent as an unencrypted DNS query. This has the potential to result in passwords and other sensitive information being sent in cleartext without the user being aware.
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Analysis
by VulDB Data Team • 12/29/2022
CVE-2015-9231 represents a significant information disclosure vulnerability in iTerm2 version 3.0.0 and related unreleased versions that demonstrates a critical flaw in application security design. This vulnerability stems from a newly introduced default feature that automatically detects URLs within the terminal interface, specifically when text is under the cursor or selected. The implementation flaw occurs when the application attempts to validate whether the highlighted text constitutes a valid URL by sending it as an unencrypted DNS query to resolve the domain. This behavior violates fundamental security principles by exposing potentially sensitive data through network traffic without user consent or awareness, creating an attack surface that adversaries can exploit to intercept authentication credentials and other confidential information.
The technical implementation of this vulnerability aligns with CWE-200, which addresses information exposure, and specifically demonstrates how insecure data handling can occur in client-side applications. The flaw operates at the network communication level where the application fails to properly sanitize or encrypt data before transmission, resulting in cleartext exposure of user-selected text through DNS queries. This issue particularly affects scenarios where users copy and paste authentication tokens, passwords, or other sensitive credentials that may contain domain names or URL-like patterns. The vulnerability exists because the application assumes that URL validation requires network resolution without considering that the text being validated might contain sensitive information, creating an implicit trust relationship that can be exploited.
The operational impact of CVE-2015-9231 extends beyond simple information disclosure to represent a sophisticated attack vector that can be leveraged in various threat scenarios. Network monitoring tools, packet analyzers, or man-in-the-middle attackers positioned within the network can capture these DNS queries and extract sensitive information that users believe to be secure within their terminal sessions. This vulnerability particularly affects environments where iTerm2 is used in corporate or sensitive operational contexts where authentication credentials, API keys, or other confidential data might be inadvertently selected and processed through this URL detection mechanism. The attack surface is amplified because the feature operates transparently without user notification, making it difficult for users to recognize when their sensitive information is being transmitted.
Mitigation strategies for this vulnerability should focus on implementing proper data sanitization and encryption practices in client applications, aligning with security frameworks such as the OWASP Top Ten and NIST cybersecurity guidelines. The immediate fix involves disabling the automatic URL detection feature or implementing encrypted DNS resolution for validation purposes, ensuring that sensitive data never leaves the client system in cleartext form. Organizations should also implement network monitoring to detect anomalous DNS query patterns and establish security awareness training to educate users about the risks of copying sensitive information into terminal applications. Additionally, the vulnerability highlights the importance of conducting thorough security reviews during feature development, particularly for applications that handle sensitive user data and perform network operations that could expose confidential information through seemingly benign functionality.