Cyber Threat Report: 'The Updated APT Playbook: Tales from the Kimsuky threat actor group'

This article by researchers at Rapid7 discusses recent activity by North Korean intrusion set 'Kimsuky'. Kimsuky is primarily focused on intelligence gathering and has targeted South Korean government entities, individuals involved in Korean unification, and global experts in fields of interest to the regime. According to the article, Kimsuky has updated its playbook to bypass modern security measures. Their tactics have evolved from using weaponized Office documents and ISO files to abusing shortcut files (LNK files) and, more recently, exploiting CHM files delivered via ISO, VHD, ZIP, or RAR files to execute malicious code. The article provides an in-depth analysis of an attack involving a CHM file used by Kimsuky. It details the structure of the CHM file, the use of Base64 encoded VBScript for execution, and the methods employed for system information gathering and maintaining persistence on the victim's system.

Behavior Prevention on Endpoint

Use capabilities to prevent suspicious behavior patterns from occurring on endpoint systems. This could include suspicious process, file, API call, etc. behavior.

Privileged Account Management

Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root.

Restrict Web-Based Content

Restrict use of certain websites, block downloads/attachments, block Javascript, restrict browser extensions, etc.

Network Intrusion Prevention

Use intrusion detection signatures to block traffic at network boundaries.

Software Configuration

Implement configuration changes to software (other than the operating system) to mitigate security risks associated to how the software operates.

Antivirus/Antimalware

Use signatures or heuristics to detect malicious software.

User Training

Train users to be aware of access or manipulation attempts by an adversary to reduce the risk of successful spearphishing, social engineering, and other techniques that involve user interaction.

Execution Prevention

Block execution of code on a system through application control, and/or script blocking.

Operating System Configuration

Make configuration changes related to the operating system or a common feature of the operating system that result in system hardening against techniques.

User Account Management

Manage the creation, modification, use, and permissions associated to user accounts.

Code Signing

Enforce binary and application integrity with digital signature verification to prevent untrusted code from executing.

Audit

Perform audits or scans of systems, permissions, insecure software, insecure configurations, etc. to identify potential weaknesses.

Restrict File and Directory Permissions

Restrict access by setting directory and file permissions that are not specific to users or privileged accounts.

Filter Network Traffic

Use network appliances to filter ingress or egress traffic and perform protocol-based filtering. Configure software on endpoints to filter network traffic.

SSL/TLS Inspection

Break and inspect SSL/TLS sessions to look at encrypted web traffic for adversary activity.

Account Use Policies

Configure features related to account use like login attempt lockouts, specific login times, etc.

Password Policies

Set and enforce secure password policies for accounts.

Multi-factor Authentication

Use two or more pieces of evidence to authenticate to a system; such as username and password in addition to a token from a physical smart card or token generator.

Restrict Registry Permissions

Restrict the ability to modify certain hives or keys in the Windows Registry.

Data Loss Prevention

Use a data loss prevention (DLP) strategy to categorize sensitive data, identify data formats indicative of personal identifiable information (PII), and restrict exfiltration of sensitive data.(Citation: PurpleSec Data Loss Prevention)

Exploit Protection

Use capabilities to detect and block conditions that may lead to or be indicative of a software exploit occurring.

Update Software

Perform regular software updates to mitigate exploitation risk.

Threat Intelligence Program

A threat intelligence program helps an organization generate their own threat intelligence information and track trends to inform defensive priorities to mitigate risk.

Application Isolation and Sandboxing

Restrict execution of code to a virtual environment on or in transit to an endpoint system.

User Account Control

Configure Windows User Account Control to mitigate risk of adversaries obtaining elevated process access.

Limit Access to Resource Over Network

Prevent access to file shares, remote access to systems, unnecessary services. Mechanisms to limit access may include use of network concentrators, RDP gateways, etc.

Disable or Remove Feature or Program

Remove or deny access to unnecessary and potentially vulnerable software to prevent abuse by adversaries.

Network Segmentation

Architect sections of the network to isolate critical systems, functions, or resources. Use physical and logical segmentation to prevent access to potentially sensitive systems and information. Use a DMZ to contain any internet-facing services...