CVE-2005-1796 in Ettercap
Summary
by MITRE
Format string vulnerability in the curses_msg function in the Ncurses interface (ec_curses.c) for Ettercap before 0.7.3 allows remote attackers to execute arbitrary code.
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Analysis
by VulDB Data Team • 06/02/2019
The vulnerability identified as CVE-2005-1796 represents a critical format string flaw within the Ncurses interface implementation of Ettercap, a network protocol analyzer and packet sniffer widely used for network traffic inspection and manipulation. This vulnerability specifically affects the curses_msg function located in the ec_curses.c source file, which handles message display operations within the curses-based user interface. The flaw exists in Ettercap versions prior to 0.7.3, making all earlier releases susceptible to exploitation by remote attackers who can manipulate input data to trigger the vulnerable code path. The format string vulnerability arises when user-supplied data is directly passed to printf-style functions without proper sanitization, allowing attackers to craft malicious input that can be interpreted as format specifiers.
The technical exploitation of this vulnerability occurs when the curses_msg function processes user-provided strings that contain format specifiers such as %s, %d, or %x, which can be manipulated to read from memory locations or write to specific addresses. Attackers can leverage this flaw to execute arbitrary code on systems running vulnerable versions of Ettercap by carefully constructing input data that, when processed by the vulnerable printf-style function, causes the program to behave unpredictably. This type of vulnerability falls under CWE-134, which specifically addresses the use of format strings in functions like printf, sprintf, or fprintf without proper validation or sanitization of user input, making it a well-documented weakness in software security practices. The attack vector is particularly dangerous because it can be exploited remotely, allowing adversaries to gain unauthorized code execution privileges on target systems.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise when attackers leverage the format string exploit to gain elevated privileges or inject malicious payloads into the running Ettercap process. Network administrators and security professionals using Ettercap for network monitoring and analysis face significant risk, as the vulnerability can be exploited without requiring local access or authentication. The exploit can potentially allow attackers to read sensitive memory contents, overwrite critical program variables, or inject shellcode that executes in the context of the Ettercap process. This vulnerability directly aligns with ATT&CK technique T1059.007, which covers the use of command and scripting interpreters, as attackers could potentially leverage the code execution capability to establish persistent access or escalate privileges within the compromised network environment.
Mitigation strategies for CVE-2005-1796 primarily involve upgrading to Ettercap version 0.7.3 or later, which includes patches that properly sanitize user input before processing it through printf-style functions. Security administrators should also implement network segmentation and access controls to limit exposure of systems running Ettercap, particularly in environments where the tool is used for network monitoring. Additional defensive measures include disabling unnecessary network services, implementing proper input validation at all levels of the application stack, and monitoring for suspicious network traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and the dangers of insecure coding practices, particularly in network security tools where the attack surface is expanded due to the need for real-time data processing and user interaction. Organizations should also consider implementing automated vulnerability scanning tools to identify and remediate similar issues in their software inventory, as format string vulnerabilities often indicate broader code quality and security practice issues that require systematic review and improvement across development processes.