• Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
MUST READ

French Authorities confirm XSS.is admin arrested in Ukraine

 | 

Microsoft linked attacks on SharePoint flaws to China-nexus actors

 | 

Cisco confirms active exploitation of ISE and ISE-PIC flaws

 | 

SharePoint under fire: new ToolShell attacks target enterprises

 | 

CrushFTP zero-day actively exploited at least since July 18

 | 

Hardcoded credentials found in HPE Aruba Instant On Wi-Fi devices

 | 

MuddyWater deploys new DCHSpy variants amid Iran-Israel conflict

 | 

U.S. CISA urges to immediately patch Microsoft SharePoint flaw adding it to its Known Exploited Vulnerabilities catalog

 | 

Microsoft issues emergency patches for SharePoint zero-days exploited in "ToolShell" attacks

 | 

SharePoint zero-day CVE-2025-53770 actively exploited in the wild

 | 

Singapore warns China-linked group UNC3886 targets its critical infrastructure

 | 

U.S. CISA adds Fortinet FortiWeb flaw to its Known Exploited Vulnerabilities catalog

 | 

SECURITY AFFAIRS MALWARE NEWSLETTER ROUND 54

 | 

Security Affairs newsletter Round 533 by Pierluigi Paganini – INTERNATIONAL EDITION

 | 

Radiology Associates of Richmond data breach impacts 1.4 million people

 | 

Fortinet FortiWeb flaw CVE-2025-25257 exploited hours after PoC release

 | 

Authorities released free decryptor for Phobos and 8base ransomware

 | 

Anne Arundel Dermatology data breach impacts 1.9 million people

 | 

LameHug: first AI-Powered malware linked to Russia’s APT28

 | 

5 Features Every AI-Powered SOC Platform Needs in 2025

 | 
  • Home
  • Cyber Crime
  • Cyber warfare
  • APT
  • Data Breach
  • Deep Web
  • Digital ID
  • Hacking
  • Hacktivism
  • Intelligence
  • Internet of Things
  • Laws and regulations
  • Malware
  • Mobile
  • Reports
  • Security
  • Social Networks
  • Terrorism
  • ICS-SCADA
  • POLICIES
  • Contact me
  • Home
  • APT
  • Breaking News
  • Malware
  • Experts detected a new variant of North Korea-linked RUSTBUCKET macOS malware

Experts detected a new variant of North Korea-linked RUSTBUCKET macOS malware

Pierluigi Paganini July 03, 2023

Researchers spotted a new version of the RustBucket Apple macOS malware that supports enhanced capabilities.

Researchers from the Elastic Security Labs have spotted a new variant of the RustBucket Apple macOS malware.

In April, the security firm Jamf observed the North Korea-linked BlueNoroff APT group using a new macOS malware, dubbed RustBucket.

The group BlueNoroff is considered a group that operates under the control of the notorious North Korea-linked Lazarus APT group.

The RustBucket malware allows operators to download and execute various payloads. The attribution to the BlueNoroff APT is due to the similarities in the findings that emerged from Kaspersky’s analysis published in December 2022. The similarities include malicious tooling on macOS that closely aligns with TTPs of those employed in the campaign.

The first-stage malware was contained within an unsigned application named Internal PDF Viewer.app. Experts believe the app can only be executed by manually overriding the Gatekeeper security measure.

The stage-one simply executes various do shell script commands to download the second stage malware from the C2 using curl. The malicious code extracts the contents of the zip file to the /Users/Shared/ directory and executes a stage-two application which is also named Internal PDF Viewer.app.

The second stage malware doesn’t use AppleScript, it masquerades as a legitimate Apple bundle identifier and is signed with an ad-hoc signature.

“When the Internal PDF Viewer application is launched, the user is presented with a PDF viewing application where they can select and open PDF documents. The application, although basic, does actually operate as a functional PDF viewer.” reads the analysis published by Jamf. “A task that isn’t overly difficult using Apple’s well-built PDFKit Framework.”

The stage-two malware communicates with the C2 server to fetch the stage-three payload, which is an ad-hoc signed trojan written in the Rust language. The trojan can run on both ARM and x86 architectures.

Upon executing, the malware collects system information, including the process listing, current time and whether or not it’s running within a VM.

This third-stage payload allows the attacker to carry out a broad range of malicious activities on the system.

BlueNoroff RustBucket malware

The attribution to the BlueNoroff APt group is first based on the domain cloud[.]dnx[.]capital used in the stage-one dropper. The use of the domain was previously reported by experts from Proofpoint.

The new variant discovered by Elastic Security Labs is more evasive, at the time of its discovery the malicious code was undetected by VirusTotal, and has improved capabilities to maintain persistence.

“Our research has identified a persistence capability not previously seen in the RUSTBUCKET family of malware, leading us to believe that this family is under active development. Additionally, at the time of publication, this new variant has zero detections on VirusTotal and is leveraging a dynamic network infrastructure methodology for command and control.” reads the report published by Elastic Security Labs.

RustBucket Apple macOS malware

The analysis of the attack chain for the new variant revealed that during Stage 1, the process starts executing an AppleScript utilizing the “/usr/bin/osascript” command. The AppleScript downloads the Stage 2 binary from the C2 using cURL. 

The second-stage malware is a binary compiled in Swift (.pd), it downloads the main component from the command-and-control (C2) server. The malware is a Rust binary that gathers info of the infected system (Computer name, List of active processes, Current timestamp, Installation timestamp, System boot time, and Status of all running processes within the system) and downloads and runs additional malicious code.

Upon execution, the malware uses the downAndExec function to prepare a POST HTTP request and utilizes specific macOS APIs for various operations.

The Stage 3 malware is written to disk and utilizes NSTask to start its execution.

The threat actor behind the malware, tracked by Elastic Security Labs as REF9135, targeted a cryptocurrency company providing services to businesses such as payroll and business-to-business transactions. The profile of the victim is aligned with the one of organizations targeted by the North Korea-linked BlueNorOff APT group.

The report includes indicators of compromise and the Yara rule for the detection of the threat.

Follow me on Twitter: @securityaffairs and Facebook and Mastodon

Pierluigi Paganini

(SecurityAffairs – hacking, Malware)


facebook linkedin twitter

Apple macOS malware APT Hacking hacking news information security news malware North Korea Pierluigi Paganini RustBucket malware Security Affairs Security News

you might also like

Pierluigi Paganini July 23, 2025
French Authorities confirm XSS.is admin arrested in Ukraine
Read more
Pierluigi Paganini July 23, 2025
Microsoft linked attacks on SharePoint flaws to China-nexus actors
Read more

leave a comment

newsletter

Subscribe to my email list and stay
up-to-date!

    recent articles

    French Authorities confirm XSS.is admin arrested in Ukraine

    Cyber Crime / July 23, 2025

    Microsoft linked attacks on SharePoint flaws to China-nexus actors

    APT / July 23, 2025

    Cisco confirms active exploitation of ISE and ISE-PIC flaws

    Hacking / July 22, 2025

    SharePoint under fire: new ToolShell attacks target enterprises

    Hacking / July 22, 2025

    CrushFTP zero-day actively exploited at least since July 18

    Hacking / July 22, 2025

    To contact me write an email to:

    Pierluigi Paganini :
    pierluigi.paganini@securityaffairs.co

    LEARN MORE

    QUICK LINKS

    • Home
    • Cyber Crime
    • Cyber warfare
    • APT
    • Data Breach
    • Deep Web
    • Digital ID
    • Hacking
    • Hacktivism
    • Intelligence
    • Internet of Things
    • Laws and regulations
    • Malware
    • Mobile
    • Reports
    • Security
    • Social Networks
    • Terrorism
    • ICS-SCADA
    • POLICIES
    • Contact me

    Copyright@securityaffairs 2024

    We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
    Cookie SettingsAccept All
    Manage consent

    Privacy Overview

    This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities...
    Necessary
    Always Enabled
    Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
    Non-necessary
    Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.
    SAVE & ACCEPT