CVE-2006-6742 in LaserJet 5100
Summary
by MITRE
Multiple buffer overflows in FTP Print Server 2.4 and 2.4.5 in HP LaserJet 5000 Series printers with firmware R.25.15 or R.25.47, and HP LaserJet 5100 Series printers with firmware V.29.12, allow remote attackers to cause a denial of service (device crash) via a long string in the (1) LIST or (2) NLST command.
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Analysis
by VulDB Data Team • 03/26/2019
The vulnerability described in CVE-2006-6742 represents a critical buffer overflow flaw affecting HP LaserJet 5000 and 5100 series printers running specific firmware versions. This issue resides within the FTP Print Server component of these multifunction devices, which serves as a network interface for print job processing and file transfers. The affected printers operate with firmware versions R.25.15 and R.25.47 for the 5000 series, and V.29.12 for the 5100 series, making them susceptible to remote exploitation without requiring authentication or physical access to the device. The vulnerability specifically targets the LIST and NLST commands used in FTP protocol communications, which are fundamental operations for directory listing and file retrieval within print server environments.
The technical flaw manifests as improper input validation within the FTP Print Server implementation, where the device fails to properly sanitize or limit the length of data received in response to LIST and NLST commands. When an attacker sends a malformed payload containing an excessively long string, the device's buffer handling mechanism overflows, causing the printer's operating system to crash or become unresponsive. This buffer overflow condition occurs at the application layer of the network stack, where the printer's embedded operating system processes FTP commands without adequate bounds checking. The vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and is classified as a remote code execution risk that can be leveraged for denial of service attacks. The exploitation mechanism is straightforward and does not require specialized tools or deep technical knowledge, making it particularly dangerous in enterprise environments where these printers may be exposed to untrusted network segments.
The operational impact of this vulnerability extends beyond simple device unavailability, as it can disrupt critical printing operations within corporate networks and potentially affect business continuity. When an attacker successfully exploits this vulnerability, the affected printer becomes non-responsive and requires manual intervention to restore functionality, including possible firmware reinstallation or device rebooting. This disruption can cascade through networked printing environments where multiple devices share common network resources or where print queues are managed centrally. The vulnerability also represents a significant risk for organizations that rely on these printers for critical operations, as the device crash can occur at any time and may not be immediately detected, potentially leading to lost print jobs or delayed document processing. Network administrators may also face challenges in identifying the source of the disruption, as the attack appears to originate from legitimate network traffic patterns.
Mitigation strategies for this vulnerability require immediate action from system administrators and network security teams. The most effective approach involves applying the firmware updates provided by HP to address the buffer overflow conditions in the affected printer models. Organizations should also implement network segmentation to isolate these devices from untrusted network zones, utilizing firewalls to restrict access to the printer's FTP services and limiting the attack surface. Network monitoring solutions should be configured to detect unusual traffic patterns that may indicate exploitation attempts, particularly around the FTP port 21 connections and the specific LIST and NLST command usage. Additionally, implementing network access controls that restrict which systems can communicate with the printer's FTP services provides an additional layer of protection. Security teams should also consider disabling FTP services on these devices if they are not required for business operations, as this eliminates the attack vector entirely. The vulnerability's classification under the ATT&CK framework includes T1210 - Exploitation of Remote Services and T1499 - Endpoint Termination, highlighting the need for comprehensive network security measures to protect against such attacks that can compromise device availability and potentially serve as stepping stones for further network infiltration.