Trustwave SpiderLabs Exposes Unique Cybersecurity Threats in the Public Sector. Learn More

Trustwave SpiderLabs Exposes Unique Cybersecurity Threats in the Public Sector. Learn More

Services
Capture
Managed Detection & Response

Eliminate active threats with 24/7 threat detection, investigation, and response.

twi-managed-portal-color
Co-Managed SOC (SIEM)

Maximize your SIEM investment, stop alert fatigue, and enhance your team with hybrid security operations support.

twi-briefcase-color-svg
Advisory & Diagnostics

Advance your cybersecurity program and get expert guidance where you need it most.

tw-laptop-data
Penetration Testing

Test your physical locations and IT infrastructure to shore up weaknesses before exploitation.

twi-database-color-svg
Database Security

Prevent unauthorized access and exceed compliance requirements.

twi-email-color-svg
Email Security

Stop email threats others miss and secure your organization against the #1 ransomware attack vector.

tw-officer
Digital Forensics & Incident Response

Prepare for the inevitable with 24/7 global breach response in-region and available on-site.

tw-network
Firewall & Technology Management

Mitigate risk of a cyberattack with 24/7 incident and health monitoring and the latest threat intelligence.

Solutions
BY TOPIC
Offensive Security
Solutions to maximize your security ROI
Microsoft Exchange Server Attacks
Stay protected against emerging threats
Rapidly Secure New Environments
Security for rapid response situations
Securing the Cloud
Safely navigate and stay protected
Securing the IoT Landscape
Test, monitor and secure network objects
Why Trustwave
About Us
Awards and Accolades
Trustwave SpiderLabs Team
Trustwave Fusion Security Operations Platform
Trustwave Security Colony
Partners
Technology Alliance Partners
Key alliances who align and support our ecosystem of security offerings
Trustwave PartnerOne Program
Join forces with Trustwave to protect against the most advance cybersecurity threats
SpiderLabs Blog

Trustwave Action Response: Supply Chain Attack Using 3CX PABX Software

Overview

On March 29, a massive supply chain compromise in 3CX software resulted in malware being installed globally across multiple industries. It is similar to the other high-profile supply chain attacks like SolarWinds in that rather than targeting a single organization, the criminals target a popular service or software provided to many large organizations. With one single compromise of the supplier, dozens and potentially hundreds of organizations may fall in turn.

Trustwave is diligently monitoring the situation for exposure and associated attacks and will provide updates here as we have them.

In this case, the supplier is 3CX, a software company that makes a very popular VOIP software phone system. These 3CX software phones are very popular and by 3CX’s own count they service over 600,000 companies globally and more than 12 million users daily. Their client list contains dozens of highly recognizable corporate entities.

Affected Versions

The trojanized binary affects both Electron Windows App (versions 18.12.407 & 18.12.416) as well as Electron Mac App (versions 18.11.1213, 18.12.402, 18.12.407 & 18.12.416). Users that either installed an update (Update 7) or installed a fresh instance of these versions may be affected. As of March 30, Shodan shows close to a quarter of a million publicly exposed 3CX management systems.

DOC_19791_picture1

Figure 1: Shodan results for publicly exposed 3CX management systems

The full attack results in an Infostealer strain of malware on the victim system via a trojanized DLL.

Attack Chain

DOC_19806_attack_chain_3cx

Figure 2: 3CX Desktop App infection flow on Windows based system

 

Upon installing either the full software (via MSI) or the update (Update 7), the software will load ffmpeg.dll which, in turn, will sideload d3dcompiler_47.dll. ffmpeg.dll is then used to extract and decrypt the second stage malware from d3dcompiler_47.dll. That second stage malware is encrypted using RC4 with a static key of "3jB(2bsG#@c7", which many organizations have pointed to as a common static key used in other malware attributed to North Korean (DPRK) state sponsored threat actors.

The second stage malware will then wait seven days before attempting to download one of sixteen Windows icon files (.ICO) from a public GitHub repository (already taken down). These fully functional icon files have a base64 string appended to the end of the file which provides the malware with the URI for its C2 server. At least one of the icons was originally uploaded to GitHub on 7.Dec.2022. The macOS version does not use GitHub to retrieve its C2 server. Instead, a list of C2 servers is stored in the file encoded with a single byte XOR key.

After connecting to the C2 server defined in the .ICO file, the final malware stage will be downloaded to the victim system. This final stage is a novel, previously unseen Infostealer. The Infostealer grabs standard system info and browsing history from Chrome, Edge, Brave, and Firefox browsers. 

3CX Scanning Activity

While probably unrelated to this supply chain attack, On March 23rd and 25th, we detected suspicious scanning activity on our honeypot instances based in the United States. Scans were aimed at CVE-2022-28005, a vulnerability for 3CX Phone System Management Console. The vulnerability allows an unauthorized user to read arbitrary files on the server, leading to cleartext credential disclosure. A successfully authenticated attacker can then upload a file that overwrites a 3CX service binary, leading to Remote Code Execution.

Remediation

3CX is currently working on an update to patch the malicious code. In the meantime, 3CX recommends that users uninstall any current version and switch to the unaffected 3CX Progressive Web App (PWA) version of its software.

Attribution

Several organizations attribute this attack to North Korea (DPRK), specifically Lazarus or a sub-organization of that group. Trustwave has not confirmed any attribution at this time.

IOCs

Windows Hashes

3CXDesktopapp-18.12.407.msi

Hash Type 

Hash 

SHA256 

aa124a4b4df12b34e74ee7f6c683b2ebec4ce9a8edcf9be345823b4fdcf5d868

SHA1 

bea77d1e59cf18dce22ad9a2fad52948fd7a9efa

MD5 

f3d4144860ca10ba60f7ef4d176cc736

3CXDesktopApp.exe (v18.12.407)

Hash Type 

Hash 

SHA256 

dde03348075512796241389dfea5560c20a3d2a2eac95c894e7bbed5e85a0acc

SHA1 

6285ffb5f98d35cd98e78d48b63a05af6e4e4dea

MD5 

bb915073385dd16a846dfa318afa3c19

3CXDesktopApp.exe (v18.12.407) Additional Hashes

Hash Type 

Hash 

SHA256 

54004dfaa48ca5fa91e3304fb99559a2395301c570026450882d6aad89132a02

SHA1 

480dc408ef50be69ebcf84b95750f7e93a8a1859

MD5 

08d79e1fffa244cc0dc61f7d2036aca9

3CXDesktopApp-18.12.416.msi

Hash Type 

Hash 

SHA256 

59e1edf4d82fae4978e97512b0331b7eb21dd4b838b850ba46794d9c7a2c0983

SHA1 

bfecb8ce89a312d2ef4afc64a63847ae11c6f69e

MD5 

0eeb1c0133eb4d571178b2d9d14ce3e9

3CXDesktopApp.exe (v18.12.416)

Hash Type 

Hash 

SHA256 

fad482ded2e25ce9e1dd3d3ecc3227af714bdfbbde04347dbc1b21d6a3670405

SHA1 

8433a94aedb6380ac8d4610af643fb0e5220c5cb

MD5 

9833a4779b69b38e3e51f04e395674c6

3CXDesktopApp.exe (v18.12.416) Additional Hashes

Hash Type 

Hash 

SHA256 

a60a61bf844bc181d4540c9fac53203250a982e7c3ad6153869f01e19cc36203

SHA1 

413d9cbfcbf8d1e8304eab0aa5484f5eec5185f5

MD5 

704db9184700481a56e5100fb56496ce

 ffmpeg.dll

Hash Type 

Hash 

SHA256 

7986bbaee8940da11ce089383521ab420c443ab7b15ed42aed91fd31ce833896

SHA1 

bf939c9c261d27ee7bb92325cc588624fca75429

MD5 

74bc2d0b6680faa1a5a76b27e5479cbc

 d3dcompiler_47.dll

Hash Type 

Hash 

SHA256 

11be1803e2e307b647a8a7e02d128335c448ff741bf06bf52b332e0bbf423b03

SHA1 

20d554a80d759c50d6537dd7097fed84dd258b3e

MD5 

82187ad3f0c6c225e2fba0c867280cc9

 Final stage Infostealer malware

Hash Type 

Hash 

SHA256 

8ab3a5eaaf8c296080fadf56b265194681d7da5da7c02562953a4cb60e147423

SHA1 

3b3e778b647371262120a523eb873c20bb82beaf

MD5 

7faea2b01796b80d180399040bb69835

MacOS Hashes

3CXDesktopApp-18.11.1213.dmg

Hash Type 

Hash 

SHA256 

5407cda7d3a75e7b1e030b1f33337a56f293578ffa8b3ae19c671051ed314290

SHA1 

19f4036f5cd91c5fc411afc4359e32f90caddaac

MD5 

5729fb29e3a7a90d2528e3357bd15a4b

3CXDesktopApp.app (v18.11.1213)

Hash Type 

Hash 

SHA256 

92005051ae314d61074ed94a52e76b1c3e21e7f0e8c1d1fdd497a006ce45fa61

SHA1 

5d833bcc679db38a45111269e727ec58b75c8d31

MD5 

3703770e32820397c6e7e1e1221e6d0d

 3CXDesktopapp-latest.dmg (v18.12.416)

Hash Type 

Hash 

SHA256 

e6bbc33815b9f20b0cf832d7401dd893fbc467c800728b5891336706da0dbcec

SHA1 

3dc840d32ce86cebf657b17cef62814646ba8e98

MD5 

d5101c3b86d973a848ab7ed79cd11e5a

 3CXDesktopApp.app (v18.12.416)

Hash Type 

Hash 

SHA256 

b86c695822013483fa4e2dfdf712c5ee777d7b99cbad8c2fa2274b133481eadb

SHA1 

f3487a1324f4c11b35504751a5527bc60eb95382

MD5 

ca8c0385ce2b8bdd19423c8b98a5924b

 libffmpeg.dylib

Hash Type 

Hash 

SHA256 

a64fa9f1c76457ecc58402142a8728ce34ccba378c17318b3340083eeb7acc67

SHA1 

769383fc65d1386dd141c960c9970114547da0c2

MD5 

660ea9b8205fbd2da59fefd26ae5115c

C2 Domains

(NOTE: These Domains have been taken down, but existing infected systems may still try to reach out to these hosts)

akamaicontainer[.]com

msedgepackageinfo[.]com

akamaitechcloudservices[.]com

msstorageazure[.]com

azuredeploystore[.]com

msstorageboxes[.]com

azureonlinecloud[.]com

officeaddons[.]com

azureonlinestorage[.]com

officestoragebox[.]com

dunamistrd[.]com

pbxcloudeservices[.]com

glcloudservice[.]com

pbxphonenetwork[.]com

qwepoi123098[.]com

zacharryblogs[.]com

sbmsa[.]wiki

pbxsources[.]com

sourceslabs[.]com

journalide[.]org

visualstudiofactory[.]com

C2 URLs

https[:]//www.3cx[.]com/blog/event-trainings/

https[:]//github[.]com/IconStorages/images

https[:]//raw[.]githubusercontent[.]com/IconStorages/images/main/icon%d.ico

https[:]//akamaitechcloudservices[.]com/v2/storage

https[:]//azureonlinestorage[.]com/azure/storage

https[:]//msedgepackageinfo[.]com/microsoft-edge

https[:]//glcloudservice[.]com/v1/console

https[:]//pbxsources[.]com/exchange

https[:]//msstorageazure[.]com/window

https[:]//officestoragebox[.]com/api/session

https[:]//visualstudiofactory[.]com/workload

https[:]//azuredeploystore[.]com/cloud/services

https[:]//msstorageboxes[.]com/office

https[:]//officeaddons[.]com/technologies

https[:]//sourceslabs[.]com/downloads

https[:]//zacharryblogs[.]com/feed

https[:]//pbxcloudeservices[.]com/phonesystem

https[:]//pbxphonenetwork[.]com/voip

https[:]//msedgeupdate[.]net/Windows

https[:]//msedge[.]com/Windows

https[:]//sbmsa[.]wiki/blog/_insert

References

3CX Alert: https://www.3cx.com/blog/news/desktopapp-security-alert/

3CX Remediation: https://www.3cx.com/blog/news/desktopapp-security-alert-updates/

Latest SpiderLabs Blogs

2024 Public Sector Threat Landscape: Trustwave Threat Intelligence Briefing and Mitigation Strategies

Trustwave SpiderLabs’ 2024 Public Sector Threat Landscape: Trustwave Threat Intelligence Briefing and Mitigation Strategies report details the security issues facing public sector security teams as...

Read More

How to Create the Asset Inventory You Probably Don't Have

This is Part 12 in my ongoing project to cover 30 cybersecurity topics in 30 weekly blog posts. The full series can be found here.

Read More

Guardians of the Gateway: Identity and Access Management Best Practices

This is Part 10 in my ongoing project to cover 30 cybersecurity topics in 30 weekly blog posts. The full series can be found here.

Read More