Threat Signal Report

North Korean State-Sponsored Threat Actors Deploying "MAUI" Ransomware

description-logo Description

Today, the United States Federal Bureau of Investigation (FBI), Cybersecurity and Infrastructure Agency (CISA) and the Department of Treasury released a joint Cybersecurity Advisory on Maui Ransomware, which is attributed to state sponsored activity by the government of North Korea.


The Joint CSA provides detailed insight on the various TTPs used by the threat actors behind Maui, which has targeted the Health and Public Health Sector.


How Serious of an Issue is This?

High. As ransomware activity causes downtime, theft of confidential and personally identifiable information (PII) and other significant impact to operations, it is important to ensure that various security measures are in place, like being up to date with patching vulnerable machines/infrastructure. Also, ensuring employees are trained and up to date on various social engineering attempts and tactics used by threat actors will be a first line of defense against such attacks.


What is Maui Ransomware?

Maui ransomware is unique in a way that it requires manual execution to start the encryption routine. Maui also features a CLI (command line interface) that is used by the threat actor to target specific files to encrypt. Maui also has the ability to identify previously encrypted files due to customer headers containing the original path of the file.


Who are HIDDEN COBRA/LAZARUS/APT38/BeagleBoyz?

HIDDEN COBRA also known as Lazarus/APT38/BeagleBoyz has been atributed to the government of North Korea. Also, they have been linked to multiple high-profile, financially-motivated attacks in various parts of the world - some of which have caused massive infrastructure disruptions. Notable attacks include the 2014 attack on a major entertainment company and a 2016 Bangladeshi financial institution heist that almost netted nearly $1 Billion (USD) for the attackers. Had it not been for a misspelling in an instruction that caused a bank to flag and block thirty transactions, HIDDEN COBRA would have pulled off a heist unlike any other. Although HIDDEN COBRA failed in their attempt, they were still able to net around 81 million dollars in total.


The most recent notable attack attributed to HIDDEN COBRA was the Wannacry Ransomware attack, which resulted in massive disruption and damage worldwide to numerous organizations, especially those in manufacturing. Various estimates of the impact were in the hundreds of millions of dollars, with some estimates claiming billions. Other verticals which this group has targeted include critical infrastructures, entertainment, finance, healthcare, and telecommunication sectors across multiple countries.


Who are the BeagleBoyz?

The BeagleBoyz group is a newly identified group that is a subset of activity by the threat actors known as HIDDEN COBRA/LAZARUS/APT 38 and has been observed committing financial crimes, specifically cryptocurrency related thefts. Further information about the BeagleBoyz can be found here.


What Operating Systems are Affected?

Windows based operating systems are affected.


What is the Status of Coverage?

Fortinet customers running the latest definitions are protected against Maui with the following (AV) signatures:


W32/Ransom_Win32_MAUICRYPT.YACC5

W32/Agent.C5C2!tr

W32/PossibleThreat


Anything Else to Note?

Victims of ransomware are cautioned against paying ransoms by such organizations as CISA, NCSC, the FBI, and HHS. Payment does not guarantee files will be recovered. It may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities which could potentially be illegal according to a U.S. Department of Treasury's Office of Foreign Assets Control (OFAC) advisory.

Telemetry


Definitions

Traffic Light Protocol

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

TLP: RED

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.

TLP: AMBER

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.

TLP: GREEN

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.

TLP: WHITE

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.