Siemens has identified multiple NULL Pointer Dereference vulnerabilities affecting various SIMATIC, SIPLUS, and TIM industrial products. These vulnerabilities, assigned CVEs CVE-2023-28827, CVE-2023-30755, and CVE-2023-30756, could allow remote attackers to cause denial-of-service conditions in affected devices. The primary issue is that the web servers of these devices fail to properly handle certain requests, leading to improper resource cleanup and potential system crashes. These vulnerabilities impact several products, including versions of SIMATIC CP 1242-7, SIMATIC HMI Comfort Panels, and SIMATIC WinCC Runtime Advanced, with a CVSS v4 score ranging from 5.9 to 8.2, depending on the vulnerability.
The vulnerabilities occur when certain HTTP requests or shutdown procedures are not adequately managed, resulting in NULL pointer dereference errors. For CVE-2023-28827, the issue arises during timeouts in the watchdog, leading to pointer clean-up and a potential denial of service. CVE-2023-30755 affects the improper handling of shutdown or reboot requests, while CVE-2023-30756 involves improper handling of the Expect HTTP header. All three vulnerabilities could be exploited remotely, with varying complexity, allowing attackers to disrupt the normal functioning of these critical industrial systems.
Siemens has provided mitigation strategies to reduce the risk of exploitation. These include updating to the latest versions of affected products, such as SIMATIC CP 1242-7 V3.5.20 or higher, and SIPLUS TIM 1531 IRC V2.4.8 or later. As a precautionary measure, Siemens also recommends disabling the web server on affected systems to mitigate potential attack vectors. Additionally, Siemens advises securing network access through proper industrial security configurations and following best practices outlined in their product manuals.
CISA has recommended further defensive measures, such as minimizing network exposure of control systems, using secure VPNs for remote access, and isolating control systems from business networks. The cybersecurity agency also emphasizes the importance of performing impact analysis and risk assessment before implementing security measures. Siemens reported these vulnerabilities to CISA, but no public exploitation of the issues has been reported at the time of publication. CISA continues to track these vulnerabilities and urges organizations to stay updated on mitigation strategies.
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