CVE-2023-4694 – HP OfficeJet Pro printers are vulnerable to Den... (How to Fix)

Q: What is the severity of CVE-2023-4694?

CVE-2023-4694 has a CVSS score of 7.5 (HIGH). HP OfficeJet Pro printers are vulnerable to Denial of Service attacks when a SOAP message with a body but no header is sent to TCP port 3911. This vulnerability allows attackers to crash or disrupt printer services, affecting organizations using these specific HP printer models.

📋 TL;DR

HP OfficeJet Pro printers are vulnerable to Denial of Service attacks when a SOAP message with a body but no header is sent to TCP port 3911. This vulnerability allows attackers to crash or disrupt printer services, affecting organizations using these specific HP printer models.

💻 Affected Systems

Products:

HP OfficeJet Pro printers

Versions: Specific models not versioned - see HP advisory for affected models

Operating Systems: Printer firmware

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects specific HP OfficeJet Pro models - check HP advisory for exact model numbers. Vulnerability exists in default configuration.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Printer becomes completely unresponsive, requiring physical power cycle or service intervention to restore functionality, disrupting printing operations.

🟠

Likely Case

Temporary service disruption where printer stops responding to network requests until rebooted.

🟢

If Mitigated

Minimal impact if printers are behind firewalls with restricted access to port 3911.

🌐 Internet-Facing: MEDIUM - Printers directly exposed to internet could be targeted by scanning bots, but requires specific SOAP payload.

🏢 Internal Only: LOW - Requires attacker to have network access to printer's port 3911, typically limited to internal users.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires sending crafted SOAP message to port 3911, which is trivial for attackers with network access.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firmware updates - check HP advisory for specific versions

Vendor Advisory: https://support.hp.com/us-en/document/ish_9823639-9823677-16/hpsbpi03894

Restart Required: Yes

Instructions:

1. Visit HP support site 2. Enter printer model 3. Download latest firmware 4. Install via printer web interface or USB 5. Reboot printer

🔧 Temporary Workarounds

Network Segmentation

all

Restrict access to printer port 3911 using firewall rules

Port Blocking

all

Block TCP port 3911 at network perimeter

🧯 If You Can't Patch

Implement network segmentation to isolate printers from untrusted networks
Monitor for unusual traffic on port 3911 and implement rate limiting

🔍 How to Verify

Check if Vulnerable:

Check printer model against HP advisory list and verify firmware version

Check Version:

Access printer web interface > Settings > System > Firmware Version

Verify Fix Applied:

Verify firmware version is updated to patched version from HP advisory

📡 Detection & Monitoring

Log Indicators:

Printer service crashes
Unusual SOAP requests on port 3911

Network Indicators:

Malformed SOAP packets to port 3911
Multiple connection attempts to printer port 3911

SIEM Query:

destination_port:3911 AND protocol:TCP AND (packet_size < 100 OR contains(malformed, soap))

📊 Metadata

CVE ID: CVE-2023-4694

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published: December 14, 2023

Last Updated: November 21, 2024

🔗 References

https://support.hp.com/us-en/document/ish_9823639-9823677-16/hpsbpi03894 Vendor Advisory
https://support.hp.com/us-en/document/ish_9823639-9823677-16/hpsbpi03894 Vendor Advisory

📤 Share & Export

📄 Export Markdown 📋 Export JSON

📋 TL;DR

💻 Affected Systems

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