In the world of cybersecurity threats, advanced persistent threat (APT) groups are some of the most sophisticated and dangerous adversaries that organizations and businesses can face. These groups are typically state-sponsored and have a broad arsenal of tactics, techniques, and procedures (TTPs) at their disposal to carry out espionage, sabotage, and financial theft operations. One of the most prolific APT groups over the past decade is Kimsuky, which has been linked to North Korea’s intelligence community. This group has been active since 2012 and has been observed using a custom piece of malware called RandomQuery in a targeted campaign that focuses on information services and organizations supporting human rights activists and North Korean defectors.
Kimsuky’s Operational Mandates and Priorities
To understand why Kimsuky is targeting these specific sectors, it’s important to look at the group’s operational mandates and priorities. North Korea’s intelligence community is primarily interested in acquiring sensitive information that could provide strategic advantages to the regime. This includes information related to military capabilities, diplomatic negotiations, economic sanctions, and individuals or groups that pose a threat to the regime’s stability. Kimsuky’s activities align with these priorities, as the group has been observed targeting government agencies, think tanks, universities, and non-profit organizations in South Korea, Japan, and the United States. The group’s tactics, techniques, and procedures (TTPs) typically involve spear-phishing campaigns, social engineering tactics, and the use of custom malware to gain access to targeted systems and exfiltrate sensitive data.
Details of the latest activity cluster
The latest activity cluster associated with Kimsuky began on May 5, 2023, and uses a variant of RandomQuery that is specifically designed to enumerate files and siphon sensitive data. The malware has been distributed through phishing emails that claim to be from Daily NK, a prominent Seoul-based online publication that covers North Korean affairs. The emails include a Microsoft Compiled HTML Help (CHM) file as an attachment, which, when opened, triggers a Visual Basic Script that communicates with a remote server to retrieve the second-stage payload of RandomQuery.
Overview of Kimsuky’s Arsenal
RandomQuery, alongside FlowerPower and AppleSeed, is among the most frequently distributed tools in Kimsuky’s arsenal. FlowerPower is a malware strain used for data collection and exfiltration, while AppleSeed is used for reconnaissance and network mapping. These tools allow Kimsuky to carry out information-gathering missions and explore targeted systems for vulnerabilities that could be exploited for future attacks.
Phishing emails, execution, and information harvesting
Launching the CHM file leads to the execution of a Visual Basic Script that issues an HTTP GET request to a remote server to retrieve the second-stage payload, a VBScript version of RandomQuery. The malware then proceeds to harvest system metadata, running processes, installed applications, and files from different folders, all of which are transmitted back to the command-and-control (C2) server. The information gathered can be used to identify critical data, system configurations, and potential security weaknesses that could be exploited in future attacks.
Significance of North Korean threat groups’ expanding remit
These incidents underscore the ever-changing landscape of North Korean threat groups, whose remit not only encompasses political espionage but also sabotage and financial threats. The emergence of Kimsuky’s custom malware highlights the group’s ability to evolve and adapt to new security measures and techniques. This emphasizes the need for organizations to be vigilant and proactive in defending against cybersecurity threats.
Kimsuky’s Links to Attacks on Vulnerable IIS Servers
In a related development, Kimsuky has also been linked to attacks that weaponize vulnerable Windows Internet Information Services (IIS) servers to drop the Metasploit Meterpreter post-exploitation framework. This is then used to deploy a Go-based proxy malware, which can be used to carry out further reconnaissance and data exfiltration. The use of IIS servers underlines the importance of maintaining robust patching and vulnerability management programs to mitigate these types of threats.
Kimsuky’s use of custom malware and its focused targeting on information services and organizations supporting human rights activists and North Korean defectors highlight the group’s sophistication and strategic objectives. Organizations must remain vigilant against these types of targeted attacks by implementing robust security measures and maintaining comprehensive vulnerability management programs. It is also important to stay up-to-date on emerging threats and APT groups’ evolving TTPs to deploy effective defense strategies against increasingly complex cyber threats.