CVE-2018-20386
📋 TL;DR
This vulnerability in ARRIS SBG6580-2 cable modems allows remote attackers to retrieve administrative credentials via specific SNMP OID requests. Attackers can obtain usernames and passwords without authentication, potentially gaining full control of affected devices. This affects devices running D30GW-SEAEAGLE-1.5.2.5-GA-00-NOSH firmware.
💻 Affected Systems
- ARRIS SBG6580-2
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover allowing attackers to modify configurations, intercept network traffic, install malware, or use the device as a pivot point into internal networks.
Likely Case
Attackers gain administrative access to the modem/router, enabling them to change DNS settings, redirect traffic, or disable security features.
If Mitigated
If SNMP is disabled or properly secured, the vulnerability cannot be exploited, though default configurations are vulnerable.
🎯 Exploit Status
Exploitation requires only SNMP access and knowledge of the specific OIDs (iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0 and iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0). Public scripts and tools exist for this vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
No official patch available. Check with ARRIS/Commscope for firmware updates. If unavailable, implement workarounds.
🔧 Temporary Workarounds
Disable SNMP Service
allCompletely disable SNMP on affected devices to prevent credential exposure
Access device admin interface → Advanced → SNMP → Disable SNMP
Restrict SNMP Access
allConfigure SNMP to only allow access from trusted management IPs
Access device admin interface → Advanced → SNMP → Set allowed IPs to management network only
Change Default Credentials
allChange administrative credentials even if exposed, as attackers may have already captured them
Access device admin interface → Administration → Change Password
🧯 If You Can't Patch
- Isolate affected devices in separate VLANs with strict firewall rules
- Implement network monitoring for SNMP requests to the vulnerable OIDs
🔍 How to Verify
Check if Vulnerable:
Use snmpwalk or similar SNMP tool to query iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0 and iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0. If credentials are returned, device is vulnerable.Check Version:
Check device web interface or use SNMP to query system description OID (1.3.6.1.2.1.1.1.0)Verify Fix Applied:
After implementing workarounds, attempt the same SNMP queries. They should fail or return no data.📡 Detection & Monitoring
Log Indicators:
- SNMP authentication failures
- Multiple SNMP requests to specific OIDs
- Configuration changes from unexpected sources
Network Indicators:
- SNMP traffic to/from non-management systems
- SNMP queries for the vulnerable OIDs
- Unexpected administrative login attempts
SIEM Query:
source_port=161 AND (oid="iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0" OR oid="iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0")🔗 References
- https://github.com/ezelf/sensitivesOids/blob/master/oidpassswordleaks.csv
- https://misteralfa-hack.blogspot.com/2018/12/stringbleed-y-ahora-que-passwords-leaks.html
- https://github.com/ezelf/sensitivesOids/blob/master/oidpassswordleaks.csv
- https://misteralfa-hack.blogspot.com/2018/12/stringbleed-y-ahora-que-passwords-leaks.html
