Malware Analysis – AppleJeus: Dorusio

Fortify Security Team
Feb 18, 2021

This Malware Analysis Report (MAR) is the result of analytic efforts among the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), and the Department of Treasury (Treasury) to highlight the cyber threat to cryptocurrency posed by North Korea, formally known as the Democratic People’s Republic of Korea (DPRK), and provide mitigation recommendations. Working with U.S. government partners, FBI, CISA, and Treasury assess that Lazarus Group—which these agencies attribute to North Korean state-sponsored advanced persistent threat (APT) actors—is targeting individuals and companies, including cryptocurrency exchanges and financial service companies, through the dissemination of cryptocurrency trading applications that have been modified to include malware that facilitates theft of cryptocurrency.

This MAR highlights this cyber threat posed by North Korea and provides detailed indicators of compromise (IOCs) used by the North Korean government. The U.S. Government refers to malicious cyber activity by the North Korean government as HIDDEN COBRA. For more information on other versions of AppleJeus and recommended steps to mitigate this threat, see Joint Cybersecurity Advisory AA21-048A: AppleJeus: Analysis of North Korea’s Cryptocurrency Malware at https://www.us-cert.cisa.gov/ncas/alerts/AA21-048A.

There have been multiple versions of AppleJeus malware discovered since its initial discovery in August 2018. In most versions, the malware appears to be from a legitimate-looking cryptocurrency trading company and website, whereby an unsuspecting individual downloads a third-party application from a website that appears legitimate.

The U.S. Government has identified AppleJeus malware version—Dorusio—and associated IOCs used by the North Korean government in AppleJeus operations. Some information has been redacted from this report to preserve victim anonymity.

Dorusio, discovered in March 2020, is a legitimate-looking cryptocurrency trading software that is marketed and distributed by a company and website— Dorusio Wallet and dorusio[.]com, respectively—that appear legitimate. There are Windows and OSX versions of Dorusio Wallet. As of at least early 2020, the actual download links result in 404 errors. The download page has release notes with version revisions claiming to start with Version 1.0.0, which was released on April 15, 2019.

For a downloadable copy of IOCs, see: MAR-10322463-6.v1.stix.

Submitted Files (6)

[Redacted] (dorusio_osx_v2.1.0.dmg)

21afaceee5fab15948a5a724222c948ad17cad181bf514a680267abcce186831 (DorusioUpgrade.exe)

[Redacted] (dorusio_win_v2.1.0.msi)

78b56a1385f2a92f3c9404f71731088646aac6c2c84cc19a449976272dab418f (Dorusio.exe)

a0c461c94ba9f1573c7253666d218b3343d24bfa5d8ef270ee9bc74b7856e492 (Dorusio)

dcb232409c799f6ddfe4bc0566161c2d0b372db6095a0018e6059e34c2b79c61 (dorusio_upgrade)

Domains (1)

dorusio.com

Findings

[Redacted]

Tags

droppertrojan

Details
Name dorusio_win_v2.1.0.msi
Size 141426176 bytes
Type Composite Document File V2 Document, Little Endian, Os: Windows, Version 10.0, MSI Installer, Security: 0, Code page: 1252, Number of Words: 2, Subject: Dorusio, Author: Dorusio Service Ltd, Name of Creating Application: Advanced Installer 14.5.2 build 83143, Template: ;1033, Comments: This installer database contains the logic and data required to install Dorusio., Title: Installation Database, Keywords: Installer, MSI, Database, Number of Pages: 200
MD5 [Redacted]
SHA1 [Redacted]
SHA256 [Redacted]
SHA512 [Redacted]
ssdeep [Redacted]
Entropy [Redacted]
Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Relationships
[Redacted] Downloaded_By dorusio.com
[Redacted] Contains 78b56a1385f2a92f3c9404f71731088646aac6c2c84cc19a449976272dab418f
[Redacted] Contains 21afaceee5fab15948a5a724222c948ad17cad181bf514a680267abcce186831
Description

This Windows program from the Dorusio Wallet site is a Windows MSI Installer. This installer appears to be legitimate and will install “Dorusio.exe” (78b56a1385f2a92f3c9404f71731088646aac6c2c84cc19a449976272dab418f) in the “C:\Program Files (x86)\Dorusio” folder. It will also install “DorusioUpgrade.exe” (21afaceee5fab15948a5a724222c948ad17cad181bf514a680267abcce186831) in the “C:\Users\<username>\AppData\Roaming\DorusioSupport” folder. Immediately after installation, the installer launches “DorusioUpgrade.exe.” During installation, a Dorusio folder containing the “Dorusio.exe” application is added to the start menu.

Screenshots

Figure 1 - Screenshot of the Dorusio Wallet installation.

Figure 1 – Screenshot of the Dorusio Wallet installation.

dorusio.com

Tags

command-and-control

URLs
  • dorusio.com/dorusio_update.php
Whois

Whois for dorusio.com had the following information:
Registrar: NAMECHEAP INC
Creation Date: 2020-03-30
Registrar Registration Expiration Date: 2021-03-30

Relationships
dorusio.com Connected_From dcb232409c799f6ddfe4bc0566161c2d0b372db6095a0018e6059e34c2b79c61
dorusio.com Downloaded [Redacted]
dorusio.com Downloaded [Redacted]
Description

The domain “dorusio.com” had a legitimately signed Sectigo SSL certificate, which was “Domain Control Validated” similar to the domain certificates for previous AppleJeus domain certificates. Investigation revealed the point of contact listed for verification was support[@]dorusio.com. No other contact information was available as the administrative or technical contact for the domain.

The domain is registered with NameCheap at the IP address 198.54.115.51 with ASN 22612. This IP is on the same ASN as the AppleJeus version 5 “CoinGoTrade” IP address.

Screenshots

Figure 2 -  Screenshot of the Dorusio site.

Figure 2 – Screenshot of the Dorusio site.

Figure 3 - Screenshot of the Dorusio download page.

Figure 3 – Screenshot of the Dorusio download page.

78b56a1385f2a92f3c9404f71731088646aac6c2c84cc19a449976272dab418f

Tags

trojan

Details
Name Dorusio.exe
Size 97682432 bytes
Type PE32+ executable (GUI) x86-64, for MS Windows
MD5 6c36c8efe2ec2b12f343537d214f45e8
SHA1 69eb27395e8f23b592547b69fbaf19ad03d6a89a
SHA256 78b56a1385f2a92f3c9404f71731088646aac6c2c84cc19a449976272dab418f
SHA512 e9e72322983315d7a99e104b0a36e6301b7c78b3e93fc33c03e2e74ea1d5423b852a23a87a8ecaadf33f73ceb03b306d953b197a13542ae436c6b039ec1c00a7
ssdeep 1572864:odJvugr82jf19dUM/1T8+1VJRukUhkmG:odhg6Pm
Entropy 6.674758
Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches
97 1b60a6d35c872102f535ae6a3d7669fb7d55c43dc7e73354423fdcca01a955d6
PE Metadata
Compile Date 2019-12-16 00:00:00-05:00
Import Hash bb1d46df79ee2045d0bc2529cf6c7458
Company Name BitPay
File Description Dorusio
Internal Name Dorusio
Legal Copyright Copyright © 2020 BitPay
Product Name Dorusio
Product Version 2.1.0.0
PE Sections
MD5 Name Raw Size Entropy
f62420692d3492b34a0696beb92d52dc header 1024 2.991122
36430f041d87935dcb34adde2e7d625d .text 78234112 6.471421
ee7e02e8e2958ff79f25c8fd8b7d33e5 .rdata 15596032 6.376243
65c59271f5c2bab26a7d0838e9f04bcf .data 262144 3.484705
00406f1d9355757d80cbf48242fdf344 .pdata 2768896 6.805097
6a6a225bfe091e65d3f82654179fbc50 .00cfg 512 0.195869
786f587a97128c401be15c90fe059b72 .rodata 6144 4.219562
9efa43af7b1faae15ffbd428d0485819 .tls 512 0.136464
60d3ea61d541c9be2e845d2787fb9574 CPADinfo 512 0.122276
bf619eac0cdf3f68d496ea9344137e8b prot 512 0.000000
fb5463e289f28642cc816a9010f32981 .rsrc 102912 4.766115
fb3216031225fdb1902888e247009d0c .reloc 709120 5.476445
Packers/Compilers/Cryptors
Microsoft Visual C++ 8.0 (DLL)
Relationships
78b56a1385… Contained_Within [Redacted]
Description

This file is a 64-bit Windows executable contained within the Windows MSI Installer “dorusio_win_v2.1.0.msi.” When executed, “Dorusio.exe” loads a legitimate looking cryptocurrency wallet application with no signs of malicious activity. Aside from the “Dorusio” logo and two new services, the wallet appears to be the same as the AppleJeus version 4 “Kupay wallet.”

This application appears to be a modification of the opensource cryptocurrency wallet Copay, which is distributed by Atlanta based company BitPay. According to the website “bitpay.com,” “BitPay builds powerful, enterprise-grade tools for crypto acceptance and spending”.

In addition to application appearance being similar, a DNS request for “bitpay.com” is always sent out immediately after a DNS request for “dorusio.com” and the company listed for “Dorusio” is Bitpay.

In addition, the GitHub “Commit Hash” listed in the “Dorusio” application “638b2b1” is to a branch of Copay found at hxxps[:]//github.com/flean/copay-1.

Screenshots

Figure 4 - Screenshot of the Dorusio application.

Figure 4 – Screenshot of the Dorusio application.

Figure 5 -  Screenshot of the "Dorusio.exe" file information.

Figure 5 – Screenshot of the “Dorusio.exe” file information.

21afaceee5fab15948a5a724222c948ad17cad181bf514a680267abcce186831

Tags

trojan

Details
Name DorusioUpgrade.exe
Size 115712 bytes
Type PE32+ executable (GUI) x86-64, for MS Windows
MD5 0f39312e8eb5702647664e9ae8502ceb
SHA1 7e64fb8ec24361406ed685719d8dedc7920791d5
SHA256 21afaceee5fab15948a5a724222c948ad17cad181bf514a680267abcce186831
SHA512 3362ef6d9c24814972c9b59f2e0b57b2c3acdb4d1dd8cd5a240359bf73ae953116ef9b8d217a817ce985ca22b3bcfe01c1085b5e707a36e93a7fae36f94bfc31
ssdeep 3072:LHOKVwaew2/vN5z3bwe+F6s3yvMBhKBrF:TjwaewcPz3Me+33UF
Entropy 6.126094
Antivirus
Ahnlab Trojan/Win64.FakeCoinTrader
Avira TR/NukeSped.xmawj
BitDefender Trojan.GenericKD.34182499
Cyren W64/Trojan.ACZK-7741
ESET a variant of Win64/NukeSped.DE trojan
Emsisoft Trojan.GenericKD.34182499 (B)
Ikarus Trojan.Win64.Nukesped
K7 Trojan ( 00569b451 )
Lavasoft Trojan.GenericKD.34182499
NetGate Trojan.Win32.Malware
Symantec Trojan.Gen.MBT
TACHYON Trojan/W64.APosT.115712.B
VirusBlokAda Trojan.APosT
Zillya! Trojan.NukeSped.Win64.104
YARA Rules

No matches found.

ssdeep Matches

No matches found.

PE Metadata
Compile Date 2020-03-30 02:52:41-04:00
Import Hash 565005404f00b7def4499142ade5e3dd
PE Sections
MD5 Name Raw Size Entropy
7ad599057f9d62e659ad5265b6bf8c8e header 1024 2.724023
7b2cea9046657ec66f103b9b3f53453d .text 65536 6.457037
59a79bcabee5542c73040a87b4be2d4e .rdata 39936 5.085609
dbf3b39f579f6cafbdf3960f0a87f5f9 .data 2560 1.851526
a6f84d98a061c4cd7874a78606fff84f .pdata 4096 4.924567
9c5adf56a571e84dc0c7329a768be170 .gfids 512 1.326857
c7e574f00528a7e39d594132f836e2ca .reloc 2048 4.763069
Packers/Compilers/Cryptors
Microsoft Visual C++ 8.0 (DLL)
Relationships
21afaceee5… Contained_Within [Redacted]
Description

This file is a 64-bit Windows executable contained within the Windows MSI Installer “dorusio_win_v2.1.0.msi.” When executed, “DorusioUpgrade.exe” first installs itself as a service, which will automatically start when any user logs on. The service is installed with a description of “Automatic Dorusio Upgrade.”

After installing the service, “DorusioUpgrade.exe” has similar behavior to the upgrade components of Kupay Wallet (AppleJeus variant 4) and CoinGoTrade (AppleJeus variant 5). On startup, “DorusioUpgrade.exe” allocates memory in order to later write a file. After allocating the memory and storing the hardcoded string “Latest” in a variable, the program attempts to open a network connection. The connection is named “Dorusio Wallet 2.1.0 (Check Update Windows)”, likely to avoid suspicion from a user.

Similar to previous AppleJeus variants, “DorusioUpgrade.exe” collects some basic information from the system as well as a timestamp and places them in hard-coded format strings. Specifically, the timestamp is placed into a format string “ver=%d&timestamp=%lu” where ver is set as the 201000, possibly referring to the Dorusio Wallet version previously mentioned (Figure 5).

This basic information and hard-coded strings are sent via a POST to the command and control (C2) “dorusio.com/dorusio_update.php.” If the POST is successful (i.e. returns an HTTP response status code of 200) but fails any of multiple different checks, “DorusioUpgrade.exe” will sleep for two minutes and then regenerate the timestamp and contact the C2 again.

After receiving the payload from the C2, the program writes the payload to memory and executes the payload.

The payload could not be downloaded as the C2 server dorusio.com/dorusio_update.php is no longer accessible. In addition, the sample was not identified in open source reporting for this sample.

Screenshots