CVE-2026-46749: SINEC INS Password Hashing Vulnerability – HIGH Severity

Technical summary

CVE-2026-46749 involves improper implementation of password hashing in SINEC INS versions prior to V1.0 SP2 Update 6. The vulnerability stems from use of a static, hardcoded salt value shared globally across all users and deployments, combined with an insufficient iteration count in the hashing algorithm. This reduces the computational cost of brute-force and dictionary attacks to practical levels, violating fundamental password storage principles (CWE-760: Use of a Broken or Risky Cryptographic Algorithm). An attacker with local access to hashed credentials can precompute rainbow tables or conduct efficient offline attacks against the password database.

Business impact

Compromise of SINEC INS user credentials could grant attackers administrative or operational control over industrial network infrastructure managed by the affected application. In operational technology environments, such unauthorized access poses direct risks to process availability, safety systems, and data integrity. Organizations relying on SINEC INS for network segmentation, access control, or security monitoring in critical infrastructure may face loss of visibility and control if credentials are compromised. The threat is heightened in multi-tenant or shared infrastructure scenarios where a single compromised installation affects multiple operational units.

Affected systems

All versions of SINEC INS prior to V1.0 SP2 Update 6 are vulnerable. This includes legacy and current deployments across Siemens' industrial automation customer base. The vulnerability affects the core authentication and credential storage mechanisms, making it relevant to any organization using SINEC INS for network security or access management in industrial environments.

Exploitability

Exploitation requires local access to the system or the password database file. The CVSS vector (AV:L/AC:H/PR:H) indicates local attack surface, high complexity, and high privileges required for initial access. However, once an attacker obtains the hashed credential store, the weak salt and iteration scheme allow offline password recovery with minimal computational resources compared to properly implemented modern hashing. No public exploit code is known, and active exploitation has not been tracked in the KEV catalog, but the weakness is straightforward to weaponize once credentials are obtained.

Remediation

Siemens has addressed this flaw in SINEC INS V1.0 SP2 Update 6 and later versions. Organizations must upgrade immediately to a patched release. Interim mitigations include restricting local system access through strong OS-level access controls, encrypting password databases at rest, and monitoring for unauthorized access attempts. However, these measures do not eliminate the underlying weakness and should not delay patching.

Patch guidance

Upgrade SINEC INS to V1.0 SP2 Update 6 or later. Verify the installed version via the application's administrative interface or system information tools. Siemens recommends testing patches in non-production environments before deployment. Organizations should prioritize this update for systems managing critical operational technology networks. Consult Siemens security advisories and release notes for detailed upgrade procedures and dependencies.

Detection guidance

Review logs for multiple failed authentication attempts or unusual privilege escalation patterns that may indicate password guessing activity. Monitor file access patterns around credential storage directories. Conduct periodic password database audits to identify accounts with unexpectedly weak or reused credentials, which may indicate prior compromise. Verify installed SINEC INS versions across your deployment to identify vulnerable instances. Network intrusion detection signatures should be tuned to flag unusual access to system configuration or authentication services.

Why prioritize this

This vulnerability merits prompt attention due to its direct impact on authentication integrity in an industrial security product. While exploitation requires initial local access, the ease of offline password recovery once credentials are obtained makes it a significant privilege escalation and lateral movement risk. Industrial environments often have long system lifecycles and slower patching cycles; organizations should treat this as a near-term priority to avoid credential compromise in operational technology networks.

Risk score, explained

The CVSS 3.1 score of 7.5 (HIGH) reflects the combination of high-impact confidentiality, integrity, and availability consequences balanced against the requirement for local access and high privileges as a starting point. The score appropriately captures the severity of compromising authentication in an industrial control system context, where unauthorized access can disrupt operations. However, security teams should weight the practical risk by assessing the likelihood of local system compromise in their specific deployment model and the value of systems protected by SINEC INS.

Frequently asked questions