CVE-2005-3277 in HP-UX
Summary
by MITRE
The LPD service in HP-UX 10.20 11.11 (11i) and earlier allows remote attackers to execute arbitrary code via shell metacharacters ("`" or single backquote) in a request that is not properly handled when an error occurs, as demonstrated by killing the connection, a different vulnerability than CVE-2002-1473.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability identified as CVE-2005-3277 affects the Line Printer Daemon (LPD) service running on Hewlett-Packard Unix (HP-UX) operating systems version 10.20 through 11.11 (11i) and earlier releases. This represents a critical remote code execution flaw that exploits improper handling of shell metacharacters within LPD service requests. The vulnerability specifically manifests when the service encounters an error condition, particularly during connection termination or error processing, where unescaped backquote characters trigger unintended shell command execution. The LPD service, which traditionally handles print job queuing and spooling operations, becomes a vector for arbitrary code execution when maliciously crafted requests containing shell metacharacters are processed. This flaw operates at the application layer and leverages the inherent trust relationships within the print service architecture, making it particularly dangerous in enterprise environments where print services are commonly exposed to network traffic.
The technical implementation of this vulnerability stems from inadequate input validation and improper shell command construction within the LPD service error handling routines. When the service receives a request containing backquote characters, these metacharacters are not properly sanitized or escaped before being processed in shell contexts. The vulnerability specifically exploits the interaction between the LPD service and the underlying shell environment, where backquotes are interpreted as command substitution operators. During error conditions such as connection termination, the service's error handling code path fails to properly sanitize user input, allowing the shell to execute commands embedded within the backquote delimiters. This represents a classic command injection vulnerability that operates under CWE-78, which specifically addresses improper neutralization of special elements used in OS commands. The vulnerability demonstrates the dangerous intersection of legacy service implementations and modern security expectations, where older Unix services were not designed with comprehensive input sanitization mechanisms.
The operational impact of CVE-2005-3277 extends beyond simple privilege escalation to encompass full system compromise and potential lateral movement within network environments. An attacker exploiting this vulnerability can execute arbitrary commands with the privileges of the LPD service account, which typically runs with elevated privileges to manage print operations. This allows for complete system takeover, including installation of backdoors, data exfiltration, and establishment of persistent access points. The vulnerability's remote exploitability means that attackers need only connect to the target system's LPD port to potentially gain system-level access without requiring local access or authentication credentials. Network scanning tools can easily identify vulnerable systems, making this a particularly attractive target for automated exploitation campaigns. The impact is compounded by the fact that LPD services are commonly enabled and exposed in enterprise environments, particularly in older HP-UX installations where security updates may not have been applied.
Mitigation strategies for CVE-2005-3277 should focus on immediate service hardening and access control measures. The most effective immediate solution involves disabling the LPD service entirely if print queuing functionality is not critical to operations, as this eliminates the attack surface entirely. When the service must remain active, administrators should implement strict network access controls using firewalls to restrict LPD service access to trusted internal networks only. The vulnerability can be addressed through patching HP-UX systems with appropriate security updates from Hewlett-Packard, which would include proper input validation and shell metacharacter sanitization in the LPD service error handling code. Additionally, implementing network segmentation and monitoring for unusual LPD service activity can help detect exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to technique T1059.007 for command and scripting interpreter, specifically shell scripting, and T1068 for exploit for privilege escalation. Organizations should also consider implementing intrusion detection systems that can identify suspicious shell command execution patterns and monitor for unauthorized access to print services, particularly in environments where print services are unnecessarily exposed to external networks.