CVE-2001-0670 in BSD
Summary
by MITRE
Buffer overflow in BSD line printer daemon (in.lpd or lpd) in various BSD-based operating systems allows remote attackers to execute arbitrary code via an incomplete print job followed by a request to display the printer queue.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2001-0670 represents a critical buffer overflow flaw within the BSD line printer daemon commonly known as in.lpd or lpd. This daemon serves as the core printing service component in various BSD-based operating systems including FreeBSD, OpenBSD, and NetBSD. The flaw manifests when the daemon processes incomplete print jobs followed by printer queue display requests, creating a scenario where attacker-controlled data can overflow fixed-size buffers in memory. This specific implementation vulnerability stems from inadequate input validation and bounds checking within the printer queue handling mechanisms of the line printer daemon.
The technical exploitation of this buffer overflow occurs through a carefully crafted sequence of print job submissions that leave the daemon in an inconsistent state. When an attacker submits an incomplete print job and subsequently requests to view the printer queue, the daemon's internal buffer management fails to properly handle the malformed data structures. This condition allows the attacker to overwrite adjacent memory locations, potentially including return addresses or function pointers, which can be manipulated to redirect program execution flow. The vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, where the buffer overflow occurs in stack memory and can be exploited to execute arbitrary code with the privileges of the running daemon process.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a pathway to gain unauthorized access to systems running vulnerable versions of BSD-based operating systems. Since the line printer daemon typically runs with elevated privileges to manage printer operations and access system resources, successful exploitation could enable attackers to execute commands with system-level access. This creates a significant risk for networked environments where multiple users might have access to print services, as the vulnerability can be exploited remotely without requiring authentication. The attack vector specifically targets the network service aspect of the daemon, making it particularly dangerous in multi-user or enterprise environments where printing services are commonly exposed to network traffic.
Mitigation strategies for CVE-2001-0670 should prioritize immediate patching of affected systems with updated versions of the BSD operating systems that contain fixed implementations of the line printer daemon. System administrators should also implement network segmentation to restrict access to printing services, particularly disabling unnecessary network access to the daemon ports. The implementation of proper input validation and bounds checking within the daemon's codebase serves as a fundamental defensive measure that aligns with the ATT&CK framework's defense evasion techniques. Additionally, monitoring for unusual print job patterns and queue display requests can help detect potential exploitation attempts. Organizations should also consider implementing privilege separation mechanisms where the printing service operates with minimal required permissions, reducing the potential impact should exploitation occur. The vulnerability's classification as a remote code execution flaw necessitates comprehensive network monitoring and intrusion detection system configurations to identify and block malicious traffic patterns associated with this specific exploit vector.