1. Introduction
The Canon PIXMA Printer WLAN Credential Disclosure vulnerability allows remote attackers to obtain sensitive authentication information from affected printers. This flaw exists because the HTTP admin interface stores WLAN authentication details (WEP/WPA/WPA2) in plaintext, potentially exposing them to unauthorized access. Successful exploitation could lead to loss of confidentiality and compromise of wireless network security.
2. Technical Explanation
The vulnerability stems from insecure storage of WLAN credentials within the printer’s HTTP admin interface. An attacker with network access can retrieve this information without authentication. The Common Vulnerabilities and Exposures (CVE) identifier for this issue is CVE-2013-4614. A simple example involves an attacker using a web browser or network tool to access the printer’s admin panel and viewing the source code of pages containing WLAN configuration details, revealing plaintext passwords. Affected devices include Canon PIXMA printers with vulnerable firmware versions.
- Root cause: The printer stores WEP/WPA/WPA2 keys in plaintext within its HTTP admin interface.
- Exploit mechanism: An attacker accesses the printer’s web-based administration panel and retrieves the credentials from the source code of configuration pages.
- Scope: Canon PIXMA printers are affected. Specific vulnerable models were not specified in available documentation.
3. Detection and Assessment
To confirm vulnerability, check the printer’s firmware version and attempt to access WLAN credentials through its web interface. A quick check involves accessing the admin panel via a web browser. More thorough assessment requires examining the source code of configuration pages for plaintext passwords.
- Quick checks: Access the printer’s web administration interface (usually via its IP address in a web browser) and navigate to WLAN settings.
- Scanning: Nessus plugin ID 60601 can detect this vulnerability, but results should be verified manually.
- Logs and evidence: Examine HTTP traffic for unencrypted transmission of WLAN credentials. This is difficult without network monitoring tools.
Access the printer's web interface via a browser (e.g., http://printer_ip_address) and check for plaintext passwords in the source code of WLAN configuration pages.4. Solution / Remediation Steps
To fix this issue, set an administrative password on the device. This prevents unauthorized access to the admin interface where credentials are stored.
4.1 Preparation
- Back up printer configuration if possible. Stopping services is not required for this remediation.
- Dependencies: Ensure you have network connectivity to the printer and know its IP address. Roll back plan: If setting a password causes issues, remove it through the admin interface.
- Change window needs: No specific change window is needed, but consider impact during peak usage times. Approval may be required by IT security policy.
4.2 Implementation
- Step 1: Access the printer’s web administration panel using a web browser.
- Step 2: Navigate to the “Settings” or “Administration” section of the interface.
- Step 3: Locate the option to set an administrative password and create a strong, unique password.
- Step 4: Save the changes and restart the printer if prompted.
4.3 Config or Code Example
Before
No administrative password set - WLAN credentials visible in plaintext within admin interface source code.After
Administrative password set - Accessing WLAN configuration requires authentication, preventing direct retrieval of credentials.4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this type of issue. Least privilege reduces the impact if an attacker gains access. Secure defaults should avoid storing sensitive information in plaintext. A patch cadence ensures timely application of security updates.
- Practice 1: Implement least privilege to limit access to printer administration interfaces.
- Practice 2: Enforce secure defaults by requiring strong passwords and avoiding storage of sensitive data in plaintext.
4.5 Automation (Optional)
Automating this fix is difficult without specific printer management tools. Scripting may be possible using SNMP, but requires detailed knowledge of the printer’s MIB structure.
# No automation script provided due to complexity and lack of standardized APIs for Canon PIXMA printers.5. Verification / Validation
- Post-fix check: Access the printer’s web interface and attempt to view WLAN settings without logging in. You should be redirected to a login page.
- Re-test: Re-examine the source code of configuration pages for plaintext passwords; they should no longer be visible.
- Smoke test: Print a test page to confirm basic printing functionality is working correctly.
- Monitoring: Monitor printer logs for failed authentication attempts on the admin interface, which could indicate unauthorized access attempts.
Access the printer's web interface and attempt to view WLAN settings without logging in. Expected output: redirection to a login page.6. Preventive Measures and Monitoring
Update security baselines to include requirements for strong passwords on all network devices, including printers. Implement CI/CD pipelines with static code analysis (SAST) tools if custom firmware is used. Establish a regular patch or configuration review cycle to address vulnerabilities promptly.
- Baselines: Update security baselines to require administrative passwords and secure configurations for all network printers.
- Pipelines: If applicable, integrate SAST into the firmware development pipeline to identify insecure storage of credentials.
- Asset and patch process: Implement a regular patch review cycle (e.g., monthly) to ensure timely application of security updates.
7. Risks, Side Effects, and Roll Back
Setting an administrative password may occasionally cause compatibility issues with older software or network configurations. If this occurs, remove the password through the admin interface. Ensure you have a record of the original configuration if needed for troubleshooting.
- Risk or side effect 2: Forgotten password – document the password securely and establish a recovery process.
- Roll back: Access the printer’s web administration panel, navigate to the “Settings” section, and remove the administrative password. Restart the printer if prompted.
8. References and Resources
- Vendor advisory or bulletin: https://seclists.org/fulldisclosure/2013/Jun/145
- NVD or CVE entry: CVE-2013-4614
- Product or platform documentation relevant to the fix: http://www.mattandreko.com/2013/06/canon-y-u-no-security.html