The Russian state-sponsored menace actor generally known as APT29 has been linked to a sophisticated phishing marketing campaign that is focusing on diplomatic entities throughout Europe with a brand new variant of WINELOADER and a beforehand unreported malware loader codenamed GRAPELOADER.
“Whereas the improved WINELOADER variant remains to be a modular backdoor utilized in later phases, GRAPELOADER is a newly noticed initial-stage instrument used for fingerprinting, persistence, and payload supply,” Examine Level stated in a technical evaluation printed earlier this week.
“Regardless of differing roles, each share similarities in code construction, obfuscation, and string decryption. GRAPELOADER refines WINELOADER’s anti-analysis strategies whereas introducing extra superior stealth strategies.”
The usage of WINELOADER was first documented by Zscaler ThreatLabz in February 2024, with the assaults leveraging wine-tasting lures to contaminate diplomatic employees programs.
Whereas the marketing campaign was first attributed to a menace exercise cluster named SPIKEDWINE, a subsequent evaluation by Google-owned Mandiant related it to the APT29 (aka Cozy Bear or Midnight Blizzard) hacking group, which is affiliated with Russia’s Overseas Intelligence Service (SVR).
The newest set of assaults entails sending e mail invitations impersonating an unspecified European Ministry of Overseas Affairs to targets for wine-tasting occasions, coaxing them into clicking a hyperlink that triggers the deployment of GRAPELOADER by the use of a malware-laced ZIP archive (“wine.zip”). The emails had been despatched from the domains bakenhof[.]com and silry[.]com.
The marketing campaign is alleged to have primarily singled out a number of European international locations with a selected give attention to Ministries of Overseas Affairs, in addition to different international locations’ embassies in Europe. There are indications that diplomats based mostly within the Center East may have been focused.
The ZIP archive accommodates three information: A DLL (“AppvIsvSubsystems64.dll”) that serves as a dependency for operating a legit PowerPoint executable (“wine.exe”), which is then exploited for DLL side-loading to launch a malicious DLL (“ppcore.dll”). The sideloaded malware capabilities as a loader (i.e., GRAPELOADER) to drop the primary payload.
The malware beneficial properties persistence by modifying the Home windows Registry to make sure that the “wine.exe” executable is launched each time the system is rebooted.
GRAPELOADER, along with incorporating anti-analysis strategies like string obfuscation and runtime API resolving, is designed to gather fundamental details about the contaminated host and exfiltrate it to an exterior server with a purpose to retrieve the next-stage shellcode.
Though the precise nature of the payload is unclear, Examine Level stated it recognized up to date WINELOADER artifacts uploaded to the VirusTotal platform with compilation timestamps matching that of “AppvIsvSubsystems64.dll.”
“With this data, and the truth that GRAPELOADER changed ROOTSAW, an HTA downloader utilized in previous campaigns to ship WINELOADER, we consider that GRAPELOADER finally results in the deployment of WINELOADER,” the cybersecurity firm stated.
The findings come as HarfangLab detailed Gamaredon’s PteroLNK VBScript malware, which is utilized by the Russian menace actor to contaminate all related USB drives with VBScript or PowerShell variations of the trojan horse. The PteroLNK samples had been uploaded to VirusTotal between December 2024 and February 2025 from Ukraine, a main goal of the hacking group.
“Each instruments, when deployed on a system, repeatedly try to detect related USB drives, with a purpose to drop LNK information and in some instances additionally a replica of PteroLNK onto them,” ESET famous in September 2024. “Clicking on a LNK file can, relying on the actual PteroLNK model that created it, both straight retrieve the subsequent stage from a C2 server, or execute a PteroLNK copy to obtain further payloads.”
The French cybersecurity agency described PteroLNK VBScript information as closely obfuscated and liable for dynamically developing a downloader and an LNK dropper throughout execution. Whereas the downloader is scheduled to execute each 3 minutes, the LNK dropper script is configured to run each 9 minutes.
The downloader employs a modular, multi-stage construction to achieve out to a distant server and fetch further malware. The LNK dropper, alternatively, propagates by means of native and community drives, changing current .pdf, .docx, and .xlsx information within the root of the listing with misleading shortcut counterparts and hiding the unique information. These shortcuts, when launched, are engineered to run PteroLNK as a substitute.
“The scripts are designed to permit flexibility for his or her operators, enabling simple modification of parameters equivalent to file names and paths, persistence mechanisms (registry keys and scheduled duties), and detection logic for safety options on the goal system,” HarfangLab stated.
It is value noting that the downloader and the LNK dropper consult with the identical two payloads that the Symantec Risk Hunter group, a part of Broadcom, revealed earlier this month as a part of an assault chain distributing an up to date model of the GammaSteel stealer –
- NTUSER.DAT.TMContainer00000000000000000001.regtrans-ms (Downloader)
- NTUSER.DAT.TMContainer00000000000000000002.regtrans-ms (LNK dropper)
“Gamaredon operates as a crucial element of Russia’s cyber operations technique, significantly in its ongoing struggle with Ukraine,” the corporate stated. “Gamaredon’s effectiveness lies not in technical sophistication however in tactical adaptability.”
“Their modus operandi combines aggressive spearphishing campaigns, fast deployment of closely obfuscated customized malware, and redundant C2 infrastructure. The group prioritizes operational influence over stealth, exemplified by pointing their DDRs to long-standing domains publicly linked to their previous operations.”
