CVE-2007-1137 in putmail
Summary
by MITRE
putmail.py in Putmail before 1.4 does not detect when a user attempts to use TLS with a server that does not support it, which causes putmail.py to send the username and password in plaintext while the user believes encryption is in use, and allows remote attackers to obtain sensitive information.
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Analysis
by VulDB Data Team • 08/20/2018
The vulnerability identified as CVE-2007-1137 resides within the putmail.py script component of the Putmail software suite prior to version 1.4. This flaw represents a critical security oversight that fundamentally undermines the integrity of email authentication mechanisms by failing to properly validate TLS support during the communication establishment phase. The issue manifests when users attempt to establish secure connections through Transport Layer Security, yet the system does not adequately verify whether the target mail server actually supports TLS encryption capabilities.
The technical implementation flaw stems from inadequate error handling and protocol validation within the putmail.py script. When a user initiates a connection attempt with TLS enabled, the script fails to perform proper negotiation checks with the remote server to confirm TLS availability and compatibility. This absence of validation creates a dangerous false sense of security where users believe their credentials are being transmitted securely through encrypted channels while the underlying communication protocol silently reverts to unencrypted plaintext transmission.
This vulnerability directly maps to CWE-319, which addresses the exposure of sensitive information through improper use of encryption. The operational impact is severe as it allows remote attackers to intercept and capture authentication credentials during the email transmission process. Attackers can exploit this weakness by positioning themselves within the network traffic path to capture the plaintext username and password combinations that are transmitted despite the user's belief that encryption is active.
The security implications extend beyond simple credential theft to encompass potential unauthorized access to email accounts and associated sensitive data. This vulnerability creates an attack surface that aligns with ATT&CK technique T1071.004, which focuses on application layer protocol command and control communications. The flaw essentially provides adversaries with a method to bypass security controls designed to protect authentication data through encryption mechanisms.
Organizations using affected versions of Putmail software face significant risk of credential compromise and potential account takeover scenarios. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous in environments where email authentication is critical for business operations. The lack of proper TLS detection means that even when users explicitly configure their clients for secure connections, the system silently degrades to insecure transmission modes.
Mitigation strategies should include immediate upgrade to Putmail version 1.4 or later, which incorporates proper TLS validation mechanisms. Additionally, administrators should implement network monitoring to detect anomalous traffic patterns that might indicate credential interception attempts. The fix addresses the root cause by implementing robust TLS negotiation verification that prevents fallback to plaintext transmission when secure connections are requested, thereby ensuring that authentication credentials are protected throughout the entire communication lifecycle.