CVE-2022-26834
📋 TL;DR
CVE-2022-26834 is an improper access control vulnerability in Rakuten Casa devices that allows remote attackers to access sensitive information stored on the device. This occurs because the devices accept HTTP connections from the WAN (internet-facing) side by default. All users of affected Rakuten Casa versions are vulnerable unless they change the default configuration.
💻 Affected Systems
- Rakuten Casa
📦 What is this software?
Casa by Rakuten
Casa by Rakuten
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attackers could access all sensitive information stored on the device, potentially including credentials, configuration data, and user information, leading to complete compromise.
Likely Case
Attackers scanning for vulnerable devices could access device information and potentially use it for further attacks or reconnaissance.
If Mitigated
With proper network segmentation and firewall rules, the impact is limited to internal network access only.
🎯 Exploit Status
Exploitation requires only HTTP access to the device from the WAN interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after AP_F_V2_0_0
Vendor Advisory: https://network.mobile.rakuten.co.jp/information/news/product/1033/
Restart Required: Yes
Instructions:
1. Access Rakuten Casa admin interface
2. Check for firmware updates
3. Apply latest firmware update
4. Restart device after update
🔧 Temporary Workarounds
Disable WAN HTTP Access
allConfigure device to disable HTTP connections from WAN interface
Access admin interface > Network Settings > Disable WAN HTTP access
Firewall Restriction
linuxBlock HTTP traffic to device from external networks
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.0.0/16 -j DROP
🧯 If You Can't Patch
- Place device behind firewall with strict inbound rules blocking HTTP from external networks
- Change default network configuration to restrict WAN access to essential services only
🔍 How to Verify
Check if Vulnerable:
Check if device responds to HTTP requests from external network on port 80Check Version:
Check device admin interface or use curl to access version endpointVerify Fix Applied:
Verify firmware version is newer than AP_F_V2_0_0 and test HTTP access from external network📡 Detection & Monitoring
Log Indicators:
- External IP addresses accessing HTTP service
- Multiple failed authentication attempts from external sources
Network Indicators:
- HTTP traffic to device from external IP addresses
- Port scanning activity targeting port 80
SIEM Query:
source_ip IN external_ips AND dest_port=80 AND protocol=HTTP