New Zloader Banking Malware Campaign Exploiting Microsoft Signature Verification

The campaign is said to have claimed 2,170 victims across 111 countries as of January 2, 2022, with most of the affected parties located in the U.S., Canada, India, Indonesia, and Australia.
It’s also notable for the fact that it wraps itself in layers of obfuscation and other detection-evasion methods to elude discovery and analysis.

The attack flow commences with the installation of a legitimate enterprise remote monitoring software called Atera, using it to upload and download arbitrary files as well as execute malicious scripts.
However, the exact mode of distributing the installer file remains unknown as yet.

One of the files is used to add exclusions to Windows Defender, while a second file proceeds to retrieve and execute next-stage payloads, including a DLL file called “appContast.dll” that, in turn, is used to run the ZLoader binary (“9092.dll”).

What stands out here is that appContast.dll is not only signed by Microsoft with a valid signature, but also that the file, originally an app resolver module (“AppResolver.dll”), has been tweaked and injected with a malicious script to load the final-stage malware.

This is made possible by exploiting a known issue tracked as CVE-2013-3900 – a WinVerifyTrust signature validation vulnerability – that allows remote attackers to execute arbitrary code via specially crafted portable executables by appending the malicious code snippet while still maintaining the validity of the file signature.

Sign Up For Threat Alerts

Loading...
Threats Icon

Dec 08, 2022

Trigona (._locked) ransomware virus

Trigona is ransomware that encrypts files and appends the "._locked" extension to filenames. Also, it...

Threats Icon

Dec 08, 2022

Threat Actors Target Exposed Remote Desktop Protocol...

Threat actors were discovered targeting open Remote Desktop Protocol (RDP) ports with variants from a...

Threats Icon

Dec 07, 2022

Redigo Backdoor Malware Targets Redis Servers

The Redigo backdoor is written in the Go programming language and targets Redis servers vulnerable...

Threats Icon

Dec 06, 2022

DuckLogs MaaS (Malware-as-a-Service) Provides Sophisticated Features

DuckLogs is MaaS (Malware-as-a-Service) advertised on cybercrime forums with a range of features including remote...

Threats Icon

Dec 05, 2022

WannaRen Returns As Life Ransomware

WannaRen ransomware appeared on the threat landscape in 2020 and reemerged in 2022 as Life...

Threats Icon

Dec 04, 2022

Alert (AA22-335A) Cuba Ransomware

The Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) are...

Threats Icon

Dec 01, 2022

UNC4191 Threat Group Targets Entities In The...

The UNC4191 threat group was discovered targeting entities in the Philippines with custom malware and...

Threats Icon

Nov 30, 2022

Emotet Leads To Quantum Ransomware Infection

Threat actors were observed using Emotet to gain access to the victim's network and deploy...

Threats Icon

Nov 29, 2022

RansomExx Upgrades to Rust

IBM Security X-Force Threat Researchers have discovered a new variant of the RansomExx ransomware that...

Threats Icon

Nov 29, 2022

Ransomware Roundup: Cryptonite Ransomware

FortiGuard Labs has reported on Cryptonite ransomware, which was found to target Microsoft Windows machines...

Threats Icon

Nov 28, 2022

Operation Typhoon: The Cyber Sea Lotus Coveting...

Cyber espionage actors, now designated by FireEye as APT32 (OceanLotus Group), are carrying out intrusions...

Threats Icon

Nov 27, 2022

IL-Cert Alert – Active phishing campaign in...

There is a new phishing campaign in Israel. The malware relies upon user execution. The...

Threats Icon

Nov 27, 2022

Emotets Vacation Is Over: No Rest For...

Emotet started as a banking Trojan in spreading via spam campaigns by imitating financial statements,...

Threats Icon

Nov 24, 2022

Aurora: A Rising Stealer Flying Under The...

Aurora is a multipurpose botnet with data collection, information stealer, downloading, and remote access Trojan...

Threats Icon

Nov 23, 2022

Analysis Of The ViperSoftX And VenomSoftX Information...

Torrents and software-sharing sites are being used to target victims across the globe with variants...