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SiliVaccine: A Look Inside North Korea’s Anti-Virus

May 2018 by Check Point

In an exclusive piece of research, Check Point Researchers have carried out a revealing investigation into North Korea’s home-grown anti-virus software, SiliVaccine. One of several interesting factors is that a key component of SiliVaccine’s code is a 10-year-old copy of one of Trend Micro, a Japanese company’s, software components.


The research journey began with our research team receiving a very rare sample of North Korea’s SiliVaccine anti-virus software from Martyn Williams, a freelance journalist with a focus on North Korean technology.
On July 8th 2014 Mr. Williams had himself received the software as a link in a suspicious email sent by someone going by the name of ‘Kang Yong Hak’, who’s mailbox has since been rendered unreachable. Upon taking a closer look, our team was able to uncover several interesting elements.
The strange email sent by ‘Kang Yong Hak’, supposedly a Japanese engineer, contained a link to a Dropbox-hosted zip file that held a copy of the SiliVaccine software, a Korean language readme file instructing how to use the software and a suspicious looking file posing as a patch for SiliVaccine.

Trend Micro’s AV Scan Engine

After detailed forensic analysis of SiliVaccine’s engine files, our team discovered exact matches of SiliVaccine and large chunks of anti-virus engine code belonging to Trend Micro, a completely separate Japan-based provider of cybersecurity solutions. Furthermore, this exact match coding had been well hidden by SiliVaccine’s authors. With Trend Micro being a Japanese company, and Japan and North Korea enjoying no official diplomatic or political relationship, this is a surprising discovery.

Of course, the purpose of an anti-virus is to block all known malware signatures. However, a deeper investigation into SiliVaccine found that it was designed to overlook one particular signature, which ordinarily it would be expected to block, and which is blocked by the Trend Micro detection engine. While it is unclear what this signature actually is, what is clear is that the North Korean regime does not want to alert its users to it.

Bundled Malware

Also found to be included in the SiliVaccine software that Marytn received was the JAKU malware. This was not necessarily part of the anti-virus but could be targeted towards journalists like Mr. Williams.
In brief, JAKU is a highly resilient botnet forming malware that has infected around 19,000 victims, primarily by malicious BitTorrent file shares. It has however been seen to target and track more specific individual victims in both South Korea and Japan, including members of International Non-Governmental Organizations (NGOs), engineering companies, academics, scientists and government employees.
Our investigation found though that the JAKU file was signed with a certificate issued to a certain ‘Ningbo Gaoxinqu zhidian Electric Power Technology Co., Ltd’, the same company that was used to sign files by another well-known APT group, ‘Dark Hotel’. Both JAKU and Dark Hotel are thought to be attributed to North Korean threat actors.

The Japanese Connection

As well as the initial email containing the copy of North Korea’s anti-virus coming from a claimed Japanese sender, there were other connections with Japan found by our researchers.

During our investigation, we discovered the names of the companies that are thought to have authored SiliVaccine, two of which are PGI (Pyonyang Gwangmyong Information Technology) and STS Tech-Service. While STS Tech-Service seems to be a North Korean establishment, it has previously worked with other companies, including those by the names of ‘Silver Star’ and ‘Magnolia’, both of which are based in Japan.

Underlying these Japanese connections, however, is the non-relationship between Japan and North Korea, who are enemies with no official diplomatic relations.


This revealing exploration into SiliVaccine may well raise suspicions of authenticity and motives of the IT security products and operations of this Hermit Kingdom. While attribution is always a difficult task in cyber security, there are many questions raised by our findings. What is clear, however, are the shady practices and questionable goals of SiliVaccine’s creators and backers. Below are the full technical details of the investigation.

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