CVE-2012-2738 in Vte
Summary
by MITRE
The VteTerminal in gnome-terminal (vte) before 0.32.2 allows remote authenticated users to cause a denial of service (long loop and CPU consumption) via an escape sequence with a large repeat count value.
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Analysis
by VulDB Data Team • 12/02/2024
The vulnerability identified as CVE-2012-2738 affects the VteTerminal component within gnome-terminal, specifically impacting versions prior to 0.32.2. This issue represents a classic denial of service vulnerability that exploits the terminal emulator's handling of escape sequences, which are control characters used to manage terminal behavior and formatting. The vulnerability stems from insufficient input validation and sanitization within the terminal's parsing logic, creating a condition where maliciously crafted escape sequences can trigger excessive computational processing.
The technical flaw manifests when the VteTerminal processes escape sequences containing large repeat count values, causing the terminal emulator to enter into prolonged looping behavior that consumes excessive CPU resources. This occurs because the terminal's parser fails to implement proper bounds checking on repeat count parameters within escape sequences, allowing attackers to specify arbitrarily large values that result in extended processing times. The vulnerability specifically targets the terminal's escape sequence handling mechanism, which is designed to interpret control codes for cursor movement, text formatting, and other terminal operations, but lacks adequate safeguards against malformed or malicious inputs.
Operationally, this vulnerability enables authenticated remote attackers to perform denial of service attacks against systems running vulnerable versions of gnome-terminal. The impact is significant as it can render the terminal emulator completely unresponsive, consuming all available CPU cycles and potentially affecting other system processes. Attackers can exploit this by sending specially crafted escape sequences through network connections or other communication channels that utilize the vulnerable terminal component, making it particularly dangerous in environments where terminal emulators are used for remote access or automated processes. The vulnerability essentially allows an attacker to create a resource exhaustion condition that can be triggered from a remote location, effectively preventing legitimate users from utilizing the terminal functionality.
Mitigation strategies for this vulnerability include updating to VteTerminal version 0.32.2 or later, which incorporates proper bounds checking and input validation for escape sequence parameters. System administrators should implement patch management processes to ensure all affected systems are updated promptly. Additionally, network segmentation and access controls can help limit the attack surface by restricting access to terminal emulators from untrusted networks. Organizations should also consider implementing monitoring solutions that can detect unusual CPU consumption patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-704, which covers improper input validation, and relates to ATT&CK technique T1499.004, which involves network denial of service attacks. The vulnerability demonstrates the importance of proper input sanitization in terminal emulators and highlights the need for robust bounds checking in parsing routines to prevent resource exhaustion attacks.