CVE-2024-5749

Executive Summary

CVE-2024-5749 is a vulnerability affecting certain HP DesignJet products that allows credential reflection, specifically enabling an attacker to view SMTP server credentials. The vulnerability has a CVSS score of 7.5 (High) and is currently unpatched. The attack vector is network-based with low complexity, requiring no privileges or user interaction. The primary impact is confidentiality breach of SMTP credentials, which could lead to further compromise of email infrastructure.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a hardware/firmware vulnerability in HP DesignJet printers.

CVSS Breakdown & Threat Level

• CVSS Score: 7.5 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

The threat level is high due to the low attack complexity and no required privileges, allowing remote attackers to extract sensitive SMTP credentials.

Deep Dive & Mechanics

The vulnerability lies in the credential reflection mechanism of HP DesignJet products. When the device processes SMTP server configuration requests, it improperly reflects credentials back to the requester without proper authentication or sanitization. This allows an unauthenticated attacker to send a crafted request to the device and receive the SMTP server credentials in the response.

The attack likely exploits a debug or diagnostic endpoint that echoes back configuration data, or a misconfigured API that returns credentials in plaintext. The exact mechanism is not publicly documented, but the core issue is insufficient access control on sensitive configuration endpoints.

Vulnerable vs. Patched Code

No specific code snippets are available for this vulnerability. The vulnerable code likely exists in the firmware's web interface or API handler that processes SMTP configuration requests. A patched version would implement proper authentication checks before returning sensitive data, and would sanitize responses to prevent credential reflection.

Exploitation & Lab Setup

Red Team

1. Reconnaissance: Identify HP DesignJet devices on the network using Shodan dorks or network scanning.
2. Exploitation: Send a crafted HTTP request to the device's configuration endpoint (e.g., /config/smtp) to trigger credential reflection.
3. Credential Extraction: Parse the response to extract SMTP server credentials.

Example exploitation request:

curl -X GET http://<target-ip>/config/smtp

Blue Team

1. Detection: Monitor for unusual requests to printer configuration endpoints.
2. Mitigation: Restrict network access to printer management interfaces using firewall rules.
3. Response: If compromised, rotate SMTP credentials immediately and isolate the device.

Indicators of Compromise (IOCs)

• Network Traffic: HTTP requests to /config/smtp or similar endpoints on HP DesignJet devices.
• Logs: Unauthorized access attempts to printer management interfaces.
• Credentials: SMTP credentials appearing in network traffic or logs.

Detection Engineering

YARA Rule

rule CVE_2024_5749_HP_DesignJet_Credential_Reflection {
    meta:
        description = "Detects credential reflection in HP DesignJet products"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-5749"
    strings:
        $smtp_config = "smtp" nocase
        $credential_reflection = "password" nocase
        $hp_header = "HP DesignJet" nocase
    condition:
        all of them
}

Sigma Rule

title: HP DesignJet Credential Reflection Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to exploit CVE-2024-5749
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: "/config/smtp"
    condition: selection
falsepositives:
    - Legitimate administrative access
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5749 HP DesignJet Credential Reflection Attempt"; flow:to_server,established; content:"/config/smtp"; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Actions:

   • Restrict network access to printer management interfaces using firewall rules.
   • Monitor for unauthorized access attempts to printer configuration endpoints.
   • Rotate any SMTP credentials that may have been exposed.

2. Long-term Fix:

   • Apply firmware updates from HP when available.
   • Implement proper authentication for all configuration endpoints.
   • Disable unnecessary debug/diagnostic endpoints.

3. Compensating Controls:

   • Use network segmentation to isolate printers from critical systems.
   • Implement intrusion detection systems to monitor for exploitation attempts.

Valters IT