Siemens TIM 1531 IRC
Act Now7.5ICS-CERT ICSA-21-159-08Jun 8, 2021
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary
The TIM 1531 IRC is vulnerable to a remote denial-of-service attack (CWE-400) that could render the device unresponsive under certain conditions. The vulnerability requires no authentication and can be triggered by a remote attacker with network access to the device. Affected versions are firmware 2.1 and earlier; Siemens has released firmware version 2.2 to resolve the issue.
What this means
What could happen
A remote attacker could cause the TIM 1531 IRC network device to become unresponsive, disrupting communications to Siemens automation systems and potentially affecting process control or monitoring capabilities across your facility.
Who's at risk
This vulnerability affects Siemens TIM 1531 IRC industrial communication devices (terminal island modules) used in automation and process control networks. Organizations operating water utilities, electric power systems, manufacturing facilities, or other critical infrastructure that rely on Siemens automation gateways should assess if these devices are deployed in their control system networks.
How it could be exploited
An attacker with network access to the device could send malformed traffic to trigger the denial-of-service condition, rendering the device unreachable. No authentication or special credentials are required—the device can be targeted if it is reachable from an attacker's network location.
Prerequisites
- Network access to the TIM 1531 IRC device (reachable from attacker network)
- No authentication required
- Device running firmware version 2.1 or earlier
Remotely exploitableNo authentication requiredLow complexity attackHigh EPSS score (78.6%)Affects network device in control systemDenial of service impact
Exploitability
High exploit probability (EPSS 78.6%)
Affected products (1)
ProductAffected VersionsFix Status
TIM 1531 IRC (incl. SIPLUS NET variants)<V2.22.2
Remediation & Mitigation
0/4
Do now
0/2HARDENINGRestrict network access to TIM 1531 IRC devices using firewalls and network segmentation; ensure devices are not directly accessible from the Internet
HARDENINGIsolate control system networks from business networks using firewalls and air gaps where possible
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HOTFIXUpdate TIM 1531 IRC (including SIPLUS NET variants) to firmware version 2.2 or later
Long-term hardening
0/1HARDENINGIf remote access to the device is required, use secure VPN connections and keep VPN software updated
CVEs (1)
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