Seculetter

About Seculetter

SecuLetter is a South Korean cybersecurity firm established in September 2015 by CEO Chasung Lim. Before founding the company, Lim spent over seven years as a cybersecurity analyst where he experienced firsthand the limitations of conventional security solutions in handling the sheer volume of daily malware threats. This experience motivated him to develop an automated, analyst-level security solution, leading to the creation of SecuLetter. The company focuses on detecting and blocking malicious code in non-executable files, a growing vector for cyberattacks that traditional signature and behavior-based systems often miss.

The firm operates on a B2B model, serving clients primarily in security-critical sectors like government, finance, and critical infrastructure. Its customer base includes major Korean institutions such as KEPCO E&C, BNK Busan Bank, and the Korea Internet & Security Agency (KISA). Revenue is generated through the sale of its security products, which can be deployed on-premise or accessed as a cloud-based subscription service. SecuLetter has pursued global expansion, establishing a presence in the Middle East, particularly Saudi Arabia, and is targeting markets in Southeast Asia.

SecuLetter's core technology is its patented automated reverse-engineering diagnostic, which analyzes files at the assembly level. This allows for the rapid detection of zero-day attacks and other advanced threats hidden in documents like MS Office, PDF, and image files, without needing to execute them in a sandbox environment. The company claims its process is significantly faster than behavior-based solutions. Its main products include 'SecuLetter Email Security' (SLE) for blocking email-based threats, 'SecuLetter File Security' (SLF) for protecting internal networks and web servers, and 'SecuLetter Cloud Security' which enhances Microsoft 365 protection. The company also offers Content Disarm and Reconstruction (CDR) technology, which removes potential threats from documents and reconstructs them as clean files.

The company has achieved significant milestones, including securing Series B funding totaling over $9 million from investors like Riyadh Valley Company and KDB Bank. In August 2023, SecuLetter was listed on the KOSDAQ stock exchange. It has also received multiple certifications and awards for its technology.