CVE-2017-7588
📋 TL;DR
CVE-2017-7588 is an authentication bypass vulnerability affecting multiple Brother printer/MFC devices. When login fails, the device incorrectly includes a valid AuthCookie in the HTTP response, allowing attackers to bypass authentication entirely. This affects all listed Brother models with default configurations.
💻 Affected Systems
- MFC-J6973CDW
- MFC-J4420DW
- MFC-8710DW
- MFC-J4620DW
- MFC-L8850CDW
- MFC-J3720
- MFC-J6520DW
- MFC-L2740DW
- MFC-J5910DW
- MFC-J6920DW
- MFC-L2700DW
- MFC-9130CW
- MFC-9330CDW
- MFC-9340CDW
- MFC-J5620DW
- MFC-J6720DW
- MFC-L8600CDW
- MFC-L9550CDW
- MFC-L2720DW
- DCP-L2540DW
- DCP-L2520DW
- HL-3140CW
- HL-3170CDW
- HL-3180CDW
- HL-L8350CDW
- HL-L2380DW
- ADS-2500W
- ADS-1000W
- ADS-1500W
📦 What is this software?
Hl Firmware by Brother
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing unauthorized access to all printer functions, configuration changes, document interception, and potential network pivoting.
Likely Case
Unauthorized access to printer management interface leading to configuration changes, document access, and potential denial of service.
If Mitigated
Limited impact if devices are isolated on separate VLANs with strict network access controls and authentication requirements.
🎯 Exploit Status
Public exploit code available on Exploit-DB (41863). Simple HTTP request manipulation required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware updates released by Brother for affected models
Vendor Advisory: https://support.brother.com/g/b/faqend.aspx?c=us&lang=en&prod=group2&faqid=faq00100611_000
Restart Required: Yes
Instructions:
1. Identify exact model number. 2. Visit Brother support website. 3. Download latest firmware for your model. 4. Upload firmware via printer web interface. 5. Reboot device after installation.
🔧 Temporary Workarounds
Network Isolation
allPlace affected devices on isolated VLAN with strict firewall rules
Disable Web Interface
allDisable HTTP/HTTPS management interface if not required
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected devices from untrusted networks
- Enable additional authentication layers (LDAP/AD integration) if supported
🔍 How to Verify
Check if Vulnerable:
Attempt login with invalid credentials and inspect HTTP response for AuthCookie header. If present, device is vulnerable.Check Version:
Check firmware version via printer web interface: Settings > Device Information > Firmware VersionVerify Fix Applied:
After firmware update, repeat vulnerability check. AuthCookie should not appear in failed login responses.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful access
- Unauthorized configuration changes
Network Indicators:
- HTTP requests to printer management interface with AuthCookie manipulation
- Unusual traffic patterns to printer web interface
SIEM Query:
source_ip=* dest_ip=printer_ip http_method=POST uri="/general/status.html" response_code=200 auth_cookie=*