CVE-2024-0794 Overview
CVE-2024-0794 is a critical buffer overflow vulnerability affecting certain HP LaserJet Pro, HP Enterprise LaserJet, and HP LaserJet Managed Printers. The vulnerability exists in the PDF rendering engine and can be triggered when the printer processes fonts embedded within a maliciously crafted PDF file, potentially leading to Remote Code Execution (RCE).
Critical Impact
Attackers can achieve Remote Code Execution on vulnerable HP LaserJet printers by sending specially crafted PDF files containing malicious embedded fonts, potentially compromising the entire device and enabling lateral movement within corporate networks.
Affected Products
- HP LaserJet Pro Printers
- HP Enterprise LaserJet Printers
- HP LaserJet Managed Printers
Discovery Timeline
- February 20, 2024 - CVE-2024-0794 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2024-0794
Vulnerability Analysis
This vulnerability is classified as an out-of-bounds read (CWE-125) that occurs during PDF font rendering operations on affected HP LaserJet printers. When the printer's PDF parser processes embedded fonts within a document, insufficient boundary checking allows an attacker to craft font data that overflows allocated memory buffers.
The buffer overflow condition enables attackers to corrupt adjacent memory regions, potentially overwriting critical control structures. Since this vulnerability is network-accessible and requires no user interaction or authentication, an attacker could remotely send a malicious print job to compromise vulnerable devices.
Printers are often overlooked in security assessments, making this vulnerability particularly dangerous in enterprise environments where these devices may have network access to sensitive resources.
Root Cause
The root cause is improper bounds checking in the font rendering subsystem when parsing TrueType or other embedded font formats within PDF documents. The printer firmware fails to validate the size and structure of font data before copying it into fixed-size memory buffers, creating an out-of-bounds read condition that can be escalated to remote code execution.
Attack Vector
The attack can be executed remotely over the network without requiring any privileges or user interaction. An attacker can exploit this vulnerability by:
- Crafting a malicious PDF document with specially constructed embedded font data
- Sending the PDF to the vulnerable printer via network printing protocols (IPP, LPR, or direct port 9100)
- When the printer processes the document, the malformed font triggers the buffer overflow
- Successful exploitation grants the attacker code execution on the printer's embedded system
The vulnerability is particularly concerning because print jobs are often submitted automatically without inspection, and printers frequently operate with elevated network privileges for scanning and document distribution functions.
Detection Methods for CVE-2024-0794
Indicators of Compromise
- Unusual network traffic originating from HP LaserJet printers to external IP addresses
- Unexpected print jobs containing PDF files from unknown sources
- Printer firmware crashes or unexpected reboots during print job processing
- Modified printer configurations or newly created administrative accounts
Detection Strategies
- Monitor print spooler logs for PDF print jobs with abnormally large embedded font tables
- Implement network segmentation to isolate printers and monitor cross-segment traffic
- Deploy IDS/IPS rules to detect malformed PDF structures in print traffic
- Audit printer firmware versions across the organization to identify unpatched devices
Monitoring Recommendations
- Enable enhanced logging on print servers to capture detailed job metadata
- Monitor for unusual outbound connections from printer IP addresses
- Implement network traffic analysis on ports 9100, 515, and 631 (common printing protocols)
- Regularly scan printer management interfaces for configuration changes
How to Mitigate CVE-2024-0794
Immediate Actions Required
- Update all affected HP LaserJet printers to the latest firmware version immediately
- Isolate vulnerable printers on a segmented network until patching is complete
- Disable direct network printing protocols where possible, routing through monitored print servers
- Review and restrict which users and systems can submit print jobs to vulnerable devices
Patch Information
HP has released security advisories and firmware updates to address this vulnerability. Administrators should review the official HP support documentation and apply the recommended firmware updates:
Download and install the latest firmware version specific to your printer model from the HP support portal.
Workarounds
- Disable PDF direct printing if not required for business operations
- Configure access control lists (ACLs) to restrict which hosts can send print jobs
- Enable printer firewall features to limit network exposure
- Route all print jobs through a centralized print server with content inspection capabilities
- Consider disabling embedded font processing if firmware configuration allows
# Example: Restrict printer access via network ACL (varies by network infrastructure)
# On Cisco IOS router/switch:
access-list 110 permit tcp 10.10.10.0 0.0.0.255 host 192.168.1.100 eq 9100
access-list 110 deny tcp any host 192.168.1.100 eq 9100
access-list 110 permit ip any any
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
