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Summary
Description
This Malware Analysis Report (MAR) is the result of analytic efforts between Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI). Working with U.S. Government partners, DHS and FBI identified Trojan malware variants used by the North Korean government. This malware variant has been identified as KEYMARBLE. The U.S. Government refers to malicious cyber activity by the North Korean government as HIDDEN COBRA. For more information on HIDDEN COBRA activity, visit https://www.us-cert.gov/hiddencobra.
DHS and FBI are distributing this MAR to enable network defense and reduce exposure to North Korean government malicious cyber activity.
This MAR includes malware descriptions related to HIDDEN COBRA, suggested response actions and recommended mitigation techniques. Users or administrators should flag activity associated with the malware, report the activity to the DHS National Cybersecurity and Communications Integration Center (NCCIC) or the FBI Cyber Watch (CyWatch), and give the activity the highest priority for enhanced mitigation.
This malware report contains analysis of one 32-bit Windows executable file, identified as a Remote Access Trojan (RAT). This malware is capable of accessing device configuration data, downloading additional files, executing commands, modifying the registry, capturing screen shots, and exfiltrating data.
rule rsa_modulus { meta: Author="NCCIC trusted 3rd party" Incident="10135536" Date = "2018/04/19" category = "hidden_cobra" family = "n/a" description = "n/a" strings: $n = "bc9b75a31177587245305cd418b8df78652d1c03e9da0cfc910d6d38ee4191d40" condition: (uint16(0) == 0x5A4D and uint16(uint32(0x3c)) == 0x4550) and any of them }
ssdeep Matches
No matches found.
PE Metadata
Compile Date
2017-04-12 11:16:04-04:00
Import Hash
fc7dab4d20f23681313b91eba653aa21
PE Sections
MD5
Name
Raw Size
Entropy
47f6fac41465e01dda5eac297ab250db
header
4096
0.627182
30d34a8f4c29d7c2feb0f6e2b102b0a4
.text
94208
6.633409
77f4a11d375f0f35b64a0c43fab947b8
.rdata
8192
5.054283
d4364f6d2f55a37f0036e9e0dc2c6a2b
.data
20480
4.416980
Packers/Compilers/Cryptors
Microsoft Visual C++ v6.0
Relationships
e23900b00f...
Connected_To
104.194.160.59
e23900b00f...
Connected_To
212.143.21.43
e23900b00f...
Connected_To
100.43.153.60
Description
This application is a malicious 32-bit Windows executable file, which functions as a RAT. When executed, it de-obfuscates its application programming interfaces (APIs) and using port 443, attempts to connect to the hard-coded IP addresses listed below. After connecting, the malware waits for further instructions.
--Begin hard-coded IP addresses-- 100.43.153.60 104.194.160.59 212.143.21.43 --End hard-coded IP addresses--
Static analysis reveals that this RAT uses a customized XOR cryptographic algorithm displayed in Figure 1 to secure its data transfers and command-and-control (C2) sessions. It is designed to accept instructions from the remote server to perform the following functions:
--Begin functions-- Download and upload files Execute secondary payloads Execute shell commands Terminate running processes Delete files Search files Set file attributes Create registry entries for storing data:(HKEY_CURRENT_USER\SOFTWARE\Microsoft\WABE\DataPath) Collect device information from installed storage devices (disk free space and their type) List running processes information Capture screenshots Collect and send information about the victim's system (operating system, CPU, MAC address, computer name, language settings, list of disk devices and their type, time elapsed since the system was started, and unique identifier of the victim's system) --End functions--
Screenshots
Figure 1 - Screenshot of the cryptographic algorithms the malware used to secure its data transfers and C2 sessions.
NCCIC would like to remind users and administrators to consider using the following best practices to strengthen the security posture of their organization's systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.
Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users' ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its "true file type" (i.e., the extension matches the file header).
Monitor users' web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumbdrives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate ACLs.
Additional information on malware incident prevention and handling can be found in NIST's Special Publication 800-83, Guide to Malware Incident Prevention & Handling for Desktops and Laptops.
NCCIC continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.gov/forms/feedback/
Document FAQ
What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact US-CERT and provide information regarding the level of desired analysis.
Can I submit malware to NCCIC? Malware samples can be submitted via three methods:
NCCIC encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on US-CERT's homepage at www.us-cert.gov.
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