# Siemens BFCClient OpenSSL vulnerabilities affect encryption

Published: 2025-08-14 · Severity: high · Sectors: manufacturing
Canonical: https://vorant.io/reports/10bf2ae3-deb3-5bf5-bb75-cfa6ffd46021/siemens-bfcclient-openssl-vulnerabilities-affect-encryption

> Five OpenSSL vulnerabilities in Siemens BFCClient prior to v2.17 enable memory disclosure, denial of service, or altered behavior via crafted certificates or encrypted data.

Siemens BFCClient versions prior to 2.17 contain five OpenSSL-related vulnerabilities that can be exploited remotely with low attack complexity. The vulnerabilities stem from underlying OpenSSL flaws affecting cryptographic operations and certificate processing. A buffer overflow in SM2 decryption (CVE-2021-3711) can overflow heap buffers by up to 62 bytes when processing specially crafted encrypted data, potentially altering application behavior or causing crashes. An out-of-bounds read in ASN.1 string handling (CVE-2021-3712) can leak private memory contents including private keys or crash the application. An infinite loop vulnerability in modular square root computation (CVE-2022-0778) affects certificate parsing and can be triggered by malformed elliptic curve parameters, causing denial of service. A type confusion vulnerability in X.400 address processing (CVE-2023-0286) during CRL checking can allow memory disclosure or denial of service. An improper certificate validation flaw (CVE-2023-0464) in policy constraint processing can trigger exponential computational use, enabling DoS attacks.

CISA reports no known public exploitation of these specific vulnerabilities at the time of advisory publication. The primary mitigation is updating BFCClient to version 2.17 or later. As an interim measure for CVE-2023-0286, organizations can disable CRL checking if operationally feasible. General ICS hardening measures including network segmentation, firewall protection, and VPN use for remote access are recommended.

## Mentioned in this report

- Vulnerabilities: CVE-2021-3711, CVE-2021-3712, CVE-2022-0778, CVE-2023-0286, CVE-2023-0464

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-226-21

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