CVE-2013-2792 in SEL-3530
Summary
by MITRE
Schweitzer Engineering Laboratories (SEL) SEL-2241, SEL-3505, and SEL-3530 RTAC master devices allow remote attackers to cause a denial of service (infinite loop) via a crafted DNP3 TCP packet.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 03/01/2019
The vulnerability identified as CVE-2013-2792 affects Schweitzer Engineering Laboratories SEL-2241, SEL-3505, and SEL-3530 RTAC master devices, which are critical components in industrial control systems and smart grid infrastructure. These devices operate as remote terminal units within electrical power systems, responsible for collecting and transmitting data from remote locations to central control centers. The affected SEL devices implement the DNP3 (Distributed Network Protocol) communication standard, which is widely used in electric utilities for supervisory control and data acquisition systems. The vulnerability represents a significant security concern as these devices are often deployed in critical infrastructure environments where reliability and availability are paramount.
The technical flaw stems from improper handling of DNP3 TCP packets within the device's network protocol stack. When a remote attacker crafts a specific malformed DNP3 TCP packet and transmits it to the affected SEL device, the device's processing logic enters an infinite loop condition. This occurs because the device fails to properly validate incoming packet structures and does not implement adequate bounds checking or input sanitization mechanisms. The vulnerability is classified as a denial of service condition where the device becomes unresponsive and ceases to function normally, effectively rendering the remote terminal unit inoperable. The infinite loop consumes system resources and prevents the device from processing legitimate network traffic or performing its required control functions.
The operational impact of this vulnerability extends beyond simple service disruption, as these devices are integral to power system monitoring and control operations. When an SEL RTAC master device becomes unresponsive due to the infinite loop, it can lead to complete loss of communication between remote field devices and the central control system. This disruption can result in operators losing visibility into critical power system parameters such as voltage levels, current flows, and equipment status. The vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous as attackers can trigger the denial of service condition from external networks. Power system operators may not immediately detect the compromise since the device simply stops responding rather than generating security alerts, potentially leading to extended periods of reduced system visibility and control.
Mitigation strategies for this vulnerability should include immediate firmware updates from Schweitzer Engineering Laboratories, which would contain patches addressing the DNP3 packet processing logic. Network segmentation and access control measures should be implemented to limit direct network access to these devices, particularly by restricting TCP port 20000 which is commonly used for DNP3 communications. Implementing network monitoring and intrusion detection systems can help detect anomalous DNP3 traffic patterns that might indicate exploitation attempts. Organizations should also consider deploying network access control lists to filter out malformed DNP3 packets at network boundaries. The vulnerability aligns with CWE-129, Input Validation, and CWE-691, Insufficient Control Flow Management, while potentially mapping to ATT&CK technique T1499.002, Network Denial of Service, within the context of industrial control systems. Regular security assessments and vulnerability management programs should be enhanced to specifically target industrial control system devices and their unique communication protocols.