A new malware campaign has been discovered targeting opposition activists in Belarus and Ukrainian military and government organizations. This campaign, attributed to the Belarus-aligned cyber group Ghostwriter, has been active since the summer of 2024. It primarily uses Microsoft Excel documents with malicious macros to deploy a variant of the PicassoLoader malware. The group, known for its long-running operations supporting Russian interests, is believed to have escalated this particular attack in November and December 2024, continuing its efforts to disrupt NATO and Ukrainian efforts via cyberattacks.
The attack chain begins with a Google Drive shared document, which contains a RAR archive file.
Inside the archive, there’s a malicious Excel workbook that triggers the execution of an obfuscated macro when macros are enabled by the victim. Once activated, the macro writes a DLL file that serves as a gateway to install the PicassoLoader malware. This malware, once executed, establishes a backdoor on the victim’s system, enabling further malicious payloads to be downloaded in the background, while a decoy Excel sheet remains visible to the victim to avoid detection.
In addition to this tactic, Ghostwriter has employed more advanced methods such as steganography. In some cases, they’ve hidden second-stage malware inside seemingly harmless JPG images, hosted on a remote URL. These images, once accessed, would deploy additional malicious software to further compromise the system. In other instances, the attackers used booby-trapped Excel documents to install a DLL named LibCMD, which executes commands like cmd.exe, enabling further manipulation of the system through a .NET assembly that runs directly in memory.
Despite Belarus not directly participating in the war in Ukraine, the country’s alignment with Russian interests has led to an active role in cyber espionage campaigns. Ghostwriter’s operations have targeted Ukrainian entities, including military and governmental organizations, using sophisticated techniques to bypass detection. The continued evolution of these attacks in 2024 highlights the increasing reliance on cyber means for state-backed espionage, making it clear that Ghostwriter’s operations will remain a significant threat for the foreseeable future.
