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Post Oak Bluetooth Traffic Systems Insufficient Entropy Vulnerability

Low RiskICS-CERT ICSA-12-335-01Sep 3, 2012
Summary

AWAM Bluetooth Reader Traffic System versions contain an insufficient entropy vulnerability in their Bluetooth encryption implementation (CWE-331). This weakness in cryptographic randomness could allow attackers within wireless range to intercept, decrypt, and forge Bluetooth communications with traffic signal readers. Post Oak Systems has not released a patch for this issue across all affected versions.

What this means
What could happen
An attacker could intercept and forge Bluetooth communications with traffic signal controllers due to weak encryption, potentially disrupting signal timing or causing traffic congestion and safety hazards at intersections.
Who's at risk
Transportation agencies operating intersection traffic control systems using AWAM Bluetooth Reader Traffic Systems should be aware of this risk. This affects any traffic signal controller that relies on wireless Bluetooth communication for timing synchronization or remote management at signalized intersections.
How it could be exploited
An attacker within Bluetooth range (typically 10-100 meters) of a traffic signal reader could capture unencrypted or weakly encrypted Bluetooth traffic, reverse-engineer the encryption scheme, and replay or forge commands to manipulate traffic signal state or timing parameters.
Prerequisites
  • Proximity to the traffic signal system (Bluetooth range)
  • No authentication required to intercept Bluetooth frames
  • Knowledge of the Bluetooth protocol implementation used by AWAM readers
No authentication requiredLow complexity exploitationNo patch availableAffects safety systems (traffic safety)
Exploitability
Low exploit probability (EPSS 0.4%)
Affected products (1)
ProductAffected VersionsFix Status
AWAM Bluetooth Reader Traffic System: vers:all/*All versionsNo fix (EOL)
Remediation & Mitigation
0/4
Do now
0/1
WORKAROUNDDeploy Bluetooth signal shielding or RF shielding enclosures around AWAM Bluetooth readers to limit wireless range and reduce attack surface
Schedule — requires maintenance window
0/2

Patching may require device reboot — plan for process interruption

HARDENINGImplement strict physical security controls around traffic signal equipment and restrict access to the area surrounding readers
HARDENINGMonitor traffic control systems for unexpected changes to signal timing or state parameters; establish alerting for anomalous Bluetooth connections
Mitigations - no patch available
0/1
AWAM Bluetooth Reader Traffic System: vers:all/* has reached End of Life. The vendor will not release a patch. Apply the following compensating controls:
HARDENINGContact Post Oak Systems regarding when a firmware update addressing insufficient entropy will be available; evaluate replacement options if no patch timeline is provided
View full CISA ICS-CERT advisory
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