CVE-2021-41418
📋 TL;DR
AriaNg versions 0.1.0 through 1.2.2 have an authentication bypass vulnerability that allows unauthenticated users to access the web interface and control Aria2 downloads. This affects all deployments using vulnerable versions without additional authentication layers. Attackers can manipulate downloads, view sensitive information, or execute arbitrary commands through Aria2 integration.
💻 Affected Systems
- AriaNg
📦 What is this software?
Ariang by Ariang Project
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the Aria2 download system allowing attackers to execute arbitrary commands on the host system through malicious downloads, steal sensitive files, or use the system for malware distribution.
Likely Case
Unauthorized access to download management interface allowing attackers to view download history, manipulate ongoing downloads, or add malicious downloads to the queue.
If Mitigated
Limited impact if proper network segmentation and authentication controls are implemented, restricting access to trusted users only.
🎯 Exploit Status
Exploitation requires only web browser access to the AriaNg interface. No authentication or special tools needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2.3 and later
Vendor Advisory: https://github.com/mayswind/AriaNg/releases
Restart Required: Yes
Instructions:
1. Download AriaNg version 1.2.3 or later from GitHub releases. 2. Replace existing AriaNg files with new version. 3. Restart web server or service hosting AriaNg. 4. Verify authentication is now required for access.
🔧 Temporary Workarounds
Web Server Authentication
allImplement HTTP basic authentication or other authentication at the web server level
# For Apache: add to .htaccess or virtual host config
AuthType Basic
AuthName "Restricted Area"
AuthUserFile /path/to/.htpasswd
Require valid-user
Network Access Control
linuxRestrict access to AriaNg interface using firewall rules
# iptables example to restrict to specific IP
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Implement reverse proxy with authentication (nginx/apache with auth)
- Place AriaNg behind VPN or internal network only, remove internet exposure
🔍 How to Verify
Check if Vulnerable:
Access AriaNg web interface without authentication. If you can see/download management interface without login prompt, system is vulnerable.Check Version:
Check AriaNg version in web interface footer or package manager: dpkg -l | grep ariang or check version.txt in installation directoryVerify Fix Applied:
Attempt to access AriaNg interface - should receive authentication prompt or be denied access.📡 Detection & Monitoring
Log Indicators:
- Unauthenticated access attempts to AriaNg endpoints
- Aria2 RPC calls from unauthenticated sources
- Unusual download activity patterns
Network Indicators:
- HTTP requests to AriaNg endpoints without authentication headers
- Aria2 RPC traffic from unexpected sources
SIEM Query:
source="web_server" AND (uri="/jsonrpc" OR uri="/aria2" OR uri="/download") AND NOT (http_auth="*" OR cookie="*session*")