Mar 24 2022

China-linked GIMMICK implant now targets macOS

Category: APT,Cyber EspionageDISC @ 8:32 am

Gimmick is a newly discovered macOS implant developed by the China-linked APT Storm Cloud and used to target organizations across Asia.

In late 2021, Volexity researchers investigated an intrusion in an environment they were monitoring and discovered a MacBook Pro running macOS 11.6 (Big Sur) that was compromised with a previously unknown macOS malware tracked as GIMMICK. The researchers explained that they have discovered Windows versions of the same implant during the past investigations.

The experts attribute the intrusion to a China-linked APT group tracked as Storm Cloud, which is known to target organizations across Asia.

The macOS version of the implant is written primarily in Objective C, while the Windows ones are in both .NET and Delphi. The implant uses public cloud hosting services (such as Google Drive) for C2 to evade detection.

Volexity worked with Apple to implement protections for the GIMMICK implant, on March 17, 2022, Apple pushed new signatures to XProtect and MRT to remove the malware.


GIMMICK should be launched directly by a user, rather than a daemon, then it installs itself as a launch agent by dropping a PLIST file with contents.

“On macOS, GIMMICK was found to support being launched as a daemon on the system or by a user. Should GIMMICK be launched directly by a user, rather than a daemon, it will install itself as a launch agent by dropping a PLIST file with contents, similar to that shown below, to /Users/<username>/Library/LaunchAgents.” reads the analysis published by Volexity. “The name of the binary, PLIST, and agent will vary per sample. In the case observed by Volexity, the implant was customized to imitate an application commonly launched by the targeted user.”

During the initialization, the implant analyzed by the experts decodes several pieces of data used by the implant for its operation using a rotating addition algorithm.

The implant also supports an uninstall function accessible by adding the argument “uninstall” on the command line. The command instructs the malicious code on removing itself and all associated files, and then kills the process.

“Storm Cloud is an advanced and versatile threat actor,  adapting its tool set to match different operating systems used by its targets.” concludes the analysis published by the experts. “The work involved in porting this malware and adapting its systems to a new operating system (macOS) is no light undertaking and suggests the threat actor behind it is well resourced, adept, and versatile.”

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Tags: cyber espionage, GIMMICK implant, macos

Mar 09 2021

Apple fixes CVE-2021-1844 RCE that affects iOS, macOS, watchOS, and Safari

Category: Security vulnerabilitiesDISC @ 10:13 am

Apple has released out-of-band security patches to address a critical iOS, macOS, watchOS, and Safari web browser to address a security flaw tracked as CVE-2021-1844.

The vulnerability was discovered by Clément Lecigne of Google’s Threat Analysis Group and Alison Huffman of Microsoft Browser Vulnerability Research. The flaw could be exploited by remote attackers to run arbitrary code on vulnerable devices by tricking users into visiting a malicious web content.

The vulnerability is caused by a memory corruption issue that could be triggered to cause arbitrary code execution when processing specially crafted web content.

“Processing maliciously crafted web content may lead to arbitrary code execution.” reads the advisory published by Apple. “Description: A memory corruption issue was addressed with improved validation.”

Apple has improved validation to address the vulnerability.

Apple has released an update for devices running iOS 14.4, iPadOS 14.4macOS Big Sur, and watchOS 7.3.1 (Apple Watch Series 3 and later). Apple also released an update to Safari for MacBooks running macOS Catalina and macOS Mojave.

In March, Pwn20wnd, the author of the jailbreaking tool “unc0ver,” has updated their software to support iOS 14.3 and earlier releases. The last release of the jailbreaking tool, unc0ver v6.0.0, now includes the exploit code for the CVE-2021-1782 vulnerability that Apple in January claimed was actively exploited by threat actors. The CVE-2021-1782 flaw is a race condition issue that resides in the iOS operating system kernel.

Tags: CVE-2021-1844, macos, safari, watchos