CVE-2021-42016
📋 TL;DR
A timing attack vulnerability in third-party components of Siemens RUGGEDCOM industrial networking devices could allow attackers to retrieve private encryption keys through side-channel analysis. This affects numerous RUGGEDCOM product models across multiple versions, potentially compromising data confidentiality and integrity in industrial control systems.
💻 Affected Systems
- RUGGEDCOM i800
- RUGGEDCOM i801
- RUGGEDCOM i802
- RUGGEDCOM i803
- RUGGEDCOM M2100
- RUGGEDCOM M2100F
- RUGGEDCOM M2200
- RUGGEDCOM M2200F
- RUGGEDCOM M969
- RUGGEDCOM M969F
- RUGGEDCOM RMC30
- RUGGEDCOM RMC8388 V4.X
- RUGGEDCOM RMC8388 V5.X
- RUGGEDCOM RP110
- RUGGEDCOM RS1600
- RUGGEDCOM RS1600F
- RUGGEDCOM RS1600T
- RUGGEDCOM RS400
- RUGGEDCOM RS400F
- RUGGEDCOM RS401
- RUGGEDCOM RS416
- RUGGEDCOM RS416F
- RUGGEDCOM RS416P
- RUGGEDCOM RS416PF
- RUGGEDCOM RS416Pv2 V4.X
- RUGGEDCOM RS416Pv2 V5.X
- RUGGEDCOM RS416v2 V4.X
- RUGGEDCOM RS416v2 V5.X
- RUGGEDCOM RS8000
- RUGGEDCOM RS8000A
- RUGGEDCOM RS8000H
- RUGGEDCOM RS8000T
- RUGGEDCOM RS900
- RUGGEDCOM RS900 (32M) V4.X
- RUGGEDCOM RS900 (32M) V5.X
- RUGGEDCOM RS900F
- RUGGEDCOM RS900G
- RUGGEDCOM RS900G (32M) V4.X
- RUGGEDCOM RS900G (32M) V5.X
- RUGGEDCOM RS900GF
- RUGGEDCOM RS900GP
- RUGGEDCOM RS900GPF
- RUGGEDCOM RS900L
- RUGGEDCOM RS900M-GETS-C01
- RUGGEDCOM RS900M-GETS-XX
- RUGGEDCOM RS900M-STND-C01
- RUGGEDCOM RS900M-STND-XX
- RUGGEDCOM RS900W
- RUGGEDCOM RS910
- RUGGEDCOM RS910L
- RUGGEDCOM RS910W
- RUGGEDCOM RS920L
- RUGGEDCOM RS920W
- RUGGEDCOM RS930L
- RUGGEDCOM RS930W
- RUGGEDCOM RS940G
- RUGGEDCOM RS940GF
- RUGGEDCOM RS969
- RUGGEDCOM RSG2100
- RUGGEDCOM RSG2100 (32M) V4.X
- RUGGEDCOM RSG2100 (32M) V5.X
- RUGGEDCOM RSG2100F
- RUGGEDCOM RSG2100P
- RUGGEDCOM RSG2100P (32M) V4.X
- RUGGEDCOM RSG2100P (32M) V5.X
- RUGGEDCOM RSG2100PF
- RUGGEDCOM RSG2200
- RUGGEDCOM RSG2200F
- RUGGEDCOM RSG2288 V4.X
- RUGGEDCOM RSG2288 V5.X
- RUGGEDCOM RSG2300 V4.X
- RUGGEDCOM RSG2300 V5.X
- RUGGEDCOM RSG2300F
- RUGGEDCOM RSG2300P V4.X
- RUGGEDCOM RSG2300P V5.X
- RUGGEDCOM RSG2300PF
- RUGGEDCOM RSG2488 V4.X
- RUGGEDCOM RSG2488 V5.X
- RUGGEDCOM RSG2488F
- RUGGEDCOM RSG907R
- RUGGEDCOM RSG908C
- RUGGEDCOM RSG909R
- RUGGEDCOM RSG910C
- RUGGEDCOM RSG920P V4.X
- RUGGEDCOM RSG920P V5.X
- RUGGEDCOM RSL910
- RUGGEDCOM RST2228
- RUGGEDCOM RST2228P
- RUGGEDCOM RST916C
- RUGGEDCOM RST916P
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could decrypt sensitive industrial control system communications, manipulate critical infrastructure operations, or gain persistent access to industrial networks.
Likely Case
Skilled attackers with network access could extract encryption keys over time, potentially decrypting sensitive operational data or establishing footholds in industrial networks.
If Mitigated
With proper network segmentation and monitoring, exploitation would be limited to isolated network segments with minimal operational impact.
🎯 Exploit Status
Timing attacks require sophisticated analysis and multiple measurement attempts. Exploitation likely requires network access to vulnerable devices.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Siemens advisory SSA-256353 for specific firmware updates
Vendor Advisory: https://cert-portal.siemens.com/productcert/html/ssa-256353.html
Restart Required: Yes
Instructions:
1. Review Siemens advisory SSA-256353. 2. Identify affected device models and firmware versions. 3. Download appropriate firmware updates from Siemens support portal. 4. Apply updates following Siemens documentation. 5. Verify update completion and functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate vulnerable devices in separate network segments with strict access controls
Access Control Lists
allImplement strict network ACLs to limit connections to vulnerable devices
🧯 If You Can't Patch
- Implement network monitoring for unusual timing analysis patterns
- Consider replacing vulnerable devices with updated models if patching not feasible
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against affected versions listed in Siemens advisory SSA-256353Check Version:
Device-specific commands vary by model - consult Siemens documentation for version checkingVerify Fix Applied:
Verify firmware version has been updated to patched version specified in Siemens advisory📡 Detection & Monitoring
Log Indicators:
- Multiple failed cryptographic operations
- Unusual timing patterns in network requests
- Repeated connection attempts to cryptographic services
Network Indicators:
- High volume of small, precisely timed requests to device cryptographic services
- Unusual network traffic patterns suggesting timing analysis
SIEM Query:
source="industrial_devices" AND (event_type="crypto_operation" OR protocol="TLS/SSL") AND count > threshold