Analysis Report

MAR-10135536-17 – North Korean Trojan: KEYMARBLE

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Alert Code


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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

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.

For a downloadable copy of IOCs, see:

Submitted Files (1)

e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09 (704d491c155aad996f16377a35732c...)

IPs (3)





Name 704d491c155aad996f16377a35732cb4
Size 126976 bytes
Type PE32 executable (GUI) Intel 80386, for MS Windows
MD5 704d491c155aad996f16377a35732cb4
SHA1 d1410d073a6df8979712dd1b6122983f66d5bef8
SHA256 e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09
SHA512 0092900bf4ca71c17a3caa225a4d7dcc60c7b58f7ffd173f46731db7f696e34b2e752aefaf9cedc27fe76fe317962a394f1be2e59bd0cffaabd9f88cc4daedcc
ssdeep 3072:IDdXEYhXxS550wwiY0Pe6Q1vLo4lJnCtea:EXEEXxcQxZ
Entropy 6.264656
Ahnlab Trojan/Win32.Agent
Antiy Trojan/Win32.AGeneric
Avira TR/Agent.rhagj
BitDefender Trojan.GenericKD.4837544
ESET a variant of Win32/NukeSped.H trojan
Emsisoft Trojan.GenericKD.4837544 (B)
Ikarus Trojan.Agent
K7 Trojan ( 0050e4401 )
McAfee GenericRXBP-FF!704D491C155A
NANOAV Trojan.Win32.Agent.eqcfki
NetGate Trojan.Win32.Malware
Quick Heal Trojan.IGENERIC
Symantec Process timed out
TACHYON Trojan/W32.Agent.126976.CTO
Zillya! Trojan.NukeSped.Win32.5
Yara Rules
hidden_cobra_consolidated.yara 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
Microsoft Visual C++ v6.0
e23900b00f... Connected_To
e23900b00f... Connected_To
e23900b00f... Connected_To

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--
--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--


Figure 1 - Screenshot of the cryptographic algorithms the malware used to secure its data transfers and C2 sessions.

  • 443 TCP

Domain Name: KRYPT.COM
Registry Domain ID: 4620809_DOMAIN_COM-VRSN
Registrar WHOIS Server:
Registrar URL:
Updated Date: 2016-02-25T03:39:29Z
Creation Date: 1998-05-04T04:00:00Z
Registry Expiry Date: 2024-05-03T04:00:00Z
Registrar:, LLC
Registrar IANA ID: 146
Registrar Abuse Contact Email:
Registrar Abuse Contact Phone: 480-624-2505
Domain Status: clientDeleteProhibited
Domain Status: clientRenewProhibited
Domain Status: clientTransferProhibited
Domain Status: clientUpdateProhibited
Name Server: NS1.CF.KRYPT.COM
Name Server: NS2.CF.KRYPT.COM
Name Server: NS3.CF.KRYPT.COM
DNSSEC: signedDelegation
DNSSEC DS Data: 2371 13 2 503AEB51F773BBCA00DB982C938895EF147DDC7D48A4E1E6FD0FE5BE7B98DA0D
URL of the ICANN Whois Inaccuracy Complaint Form:
Last update of whois database: 2018-06-28T02:39:11Z

Relationships Connected_From e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09

  • 443 TCP

Domain Name: SERVPAC.COM
Registry Domain ID: 81803816_DOMAIN_COM-VRSN
Registrar WHOIS Server:
Registrar URL:
Updated Date: 2013-12-27T04:46:10Z
Creation Date: 2001-12-31T08:29:34Z
Registry Expiry Date: 2018-12-31T08:29:34Z
Registrar:, LLC
Registrar IANA ID: 146
Registrar Abuse Contact Email:
Registrar Abuse Contact Phone: 480-624-2505
Domain Status: clientDeleteProhibited
Domain Status: clientRenewProhibited
Domain Status: clientTransferProhibited
Domain Status: clientUpdateProhibited
Name Server: NS1.SERVPAC.COM
Name Server: NS2.SERVPAC.COM
DNSSEC: unsigned
URL of the ICANN Whois Inaccuracy Complaint Form:
Last update of whois database: 2018-06-28T02:40:41Z

Relationships Connected_From e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09

  • 443 TCP

netnum: -
netname:        Nana10-LAN
descr:         Nana10-LAN
country:        IL
admin-c:        NV6695-RIPE
tech-c:         NV6695-RIPE
status:         ASSIGNED PA
mnt-by:         NV-MNT-RIPE
created:        2011-02-17T09:16:56Z
last-modified: 2011-02-17T09:16:57Z
source:         RIPE

person:         Nana 10 LTD
address:        1 Korazin str
address:        Givataim, Israel, 53583
mnt-by:         NV-MNT-RIPE
phone:         +972-73-7992000
fax-no:         +972-73-7992220
nic-hdl:        NV6695-RIPE
created:        2010-08-04T09:51:11Z
last-modified: 2011-02-17T09:01:21Z
source:         RIPE

% Information related to ''

descr:         013 Netvision Network
origin:         AS1680
mnt-by:         NV-MNT-RIPE
created:        1970-01-01T00:00:00Z
last-modified: 2009-03-26T10:55:12Z
source:         RIPE

Relationships Connected_From e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09

Relationship Summary

e23900b00f... Connected_To
e23900b00f... Connected_To
e23900b00f... Connected_To Connected_From e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09 Connected_From e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09 Connected_From e23900b00ffd67cd8dfa3283d9ced691566df6d63d1d46c95b22569b49011f09


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.

Contact Information

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:

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


August 9, 2018: Initial version

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