CVE-2025-27539: 
Telecontrol Server Basic vulnerability analysis and mitigation

A critical SQL injection vulnerability (CVE-2025-27539) has been identified in TeleControl Server Basic (All versions < V3.1.2.2). The vulnerability exists in the internally used 'VerifyUser' method, discovered and disclosed on April 16, 2025. The affected software is Siemens TeleControl Server Basic, which allows remote monitoring and control of plants via WAN/LAN (Siemens Advisory).

The vulnerability is a SQL injection flaw in the 'VerifyUser' method that could allow an unauthenticated remote attacker to bypass authorization controls. The vulnerability has received a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, and a CVSS v4.0 base score of 9.3 with vector string CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L. The vulnerability is classified as CWE-89: Improper Neutralization of Special Elements used in an SQL Command (CISA Advisory, Siemens Advisory).

If exploited, this vulnerability allows attackers to read from and write to the application's database and execute code with 'NT AUTHORITY\NetworkService' permissions. A successful attack requires the attacker to be able to access port 8000 on a system where a vulnerable version of the affected application is executed (Siemens Advisory).

Siemens has released version V3.1.2.2 which addresses this vulnerability. As a workaround, organizations are advised to restrict access to port 8000 on affected systems to trusted IP addresses only. Siemens also recommends configuring the environment according to their operational guidelines for Industrial Security (Siemens Advisory).