Threat Signal Report

Recent APT37 Activity and Chinotto, a Multi Platform Infostealer

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FortiGuard Labs is aware of reports of recent activity from APT37. APT37 is a nation-state threat actor attributed to North Korea. The latest discovery by researchers at Kaspersky Labs has revealed a sophisticated, targeted attack that utilizes the stolen credentials from Facebook and email accounts belonging to an associate of the targeted victim.

The victim was socially engineered and compelled into opening rar zipped attachments purporting to be from the trusted sender that contained a malicious Word document. The Word document is multi stage in design, and uses a malicious macro to initiate the first stage. The first stage detects the presence of AV software, and if AV is not present will initiate the second stage which is a shellcode that will download the final third stage payload.

Ultimately, after several months of dwelling undetected on the infected system, the backdoor will then download the multiplatform infostealer, "Chinotto." Windows variants were sent via spearphishing emails and Android variants were sent via SMShing texts.

What Operating Systems are Affected?

Chinoto targets Windows and Android based operating systems.

Is This Limited to Targeted Attacks?


How Serious of an Issue is This?


What is APT37?

APT37 (also known as GROUP123 and Scarcruft), attributed to North Korean threat actors, has been in operation for several years. During that time, APT37 has been attributed to the Adobe Flash zero-day attack (CVE-2018-4878) that targeted researchers based in South Korea who were performing research on North Korea. APT37 focuses on various organizations with an interest in North Korea.

APT37 is famous for exploiting vulnerabilities in the Hangul Word Processor (HWP) which is commonly used in South Korea, especially by those in the government sector. Analysis suggests that this is a very detailed and sophisticated threat actor with an arsenal of malware and exploits at their disposal that targets various verticals and organizations with specially crafted campaigns. Other vectors besides the Adobe and Hangul vulnerabilities observed were the usage of Microsoft vulnerabilities as well, specifically CVE-2017-0199 (Microsoft Office UAC bypass) and CVE-2015-2545 (Microsoft Office Encapsulated PostScript (EPS). For further details on the exploitation of HWP documents and campaigns previously analyzed, please refer to our blog here.

What is the Status of Coverage?

FortiGuard Labs has AV coverage in place for publicly available samples as:









All network IOCs are blocked by the WebFiltering client.

Any Other Suggested Mitigation?

Due to the ease of disruption and the potential for damage to daily operations, reputation, and unwanted release of personally identifiable information (PII), etc. it is important to keep all AV and IPS signatures up to date.

It is also important to ensure that all known vendor vulnerabilities are addressed and updated to protect from attackers having a foothold within a network. Attackers are well aware of the difficulty of patching and if it is determined that patching is not feasible at this time, an assessment should be conducted to determine risk.

Also, as this campaign was sent via spearphishing and smsshing - organizations are encouraged to conduct ongoing training sessions to educate and inform personnel about the latest phishing/spearphishing/smishing attacks. They also need to encourage employees to never open attachments from someone they don't know, and to always treat emails from unrecognized/untrusted senders with caution. Since it has been reported that various phishing/spearphishing/smishing attacks have been delivered via social engineering distribution mechanisms, it is crucial that end users within an organization be made aware of the various types of attacks being delivered. This can be accomplished through regular training sessions and impromptu tests using predetermined templates by an organizations' internal security department. Simple user awareness training on how to spot emails with malicious attachments or links could also help prevent initial access into the network.


Traffic Light Protocol

Color When Should it Be used? How may it be shared?


Not for disclosure, restricted to participants only.
Sources may use TLP:RED when information cannot be effectively acted upon by additional parties, and could lead to impacts on a party's privacy, reputation, or operations if misused. Recipients may not share TLP:RED information with any parties outside of the specific exchange, meeting, or conversation in which it was originally disclosed. In the context of a meeting, for example, TLP:RED information is limited to those present at the meeting. In most circumstances, TLP:RED should be exchanged verbally or in person.


Limited disclosure, restricted to participants’ organizations.
Sources may use TLP:AMBER when information requires support to be effectively acted upon, yet carries risks to privacy, reputation, or operations if shared outside of the organizations involved. Recipients may only share TLP:AMBER information with members of their own organization, and with clients or customers who need to know the information to protect themselves or prevent further harm. Sources are at liberty to specify additional intended limits of the sharing: these must be adhered to.


Limited disclosure, restricted to the community.
Sources may use TLP:GREEN when information is useful for the awareness of all participating organizations as well as with peers within the broader community or sector. Recipients may share TLP:GREEN information with peers and partner organizations within their sector or community, but not via publicly accessible channels. Information in this category can be circulated widely within a particular community. TLP:GREEN information may not be released outside of the community.


Disclosure is not limited.
Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction.