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Malware campaigns that combine phishing, obfuscated VBScript, PowerShell, and legitimate Windows applications to conceal infections targeting users in Brazil and Portugal.

The investigation covers Overlord RAT, Lampion, and an unidentified payload delivered through a malicious newdev.dll.

Rather than exploiting Windows Error Reporting itself, attackers impersonated its components and naming conventions, disguising malicious executables and scheduled tasks as routine operating system activity.

The Overlord campaign impersonated Brazilian protest notaries, sending fraudulent legal notices containing links personalized with valid CNPJ business registration numbers.

Instead of displaying documents, the links delivered VBS downloaders that retrieved executable or MSI payloads access.

Scripts concealed strings using Chr() expressions or concatenation. Downloads originated from Dropbox and Google Cloud Storage, with curl used first and PowerShell serving as a fallback in several variants.

Batch scripts requested administrative privileges, attempted Microsoft Defender exclusions, and placed files under C:\ProgramData\Microsoft\Windows\WER.

One executable, CLUpdater.exe, created two scheduled tasks using the name “Windows Error Reporting.”

Another Go-based loader checked for VMware and VirtualBox directories, copied itself into a user-profile WER directory as WerFault.exe, and established Startup-folder persistence.

The familiar filename is significant: this was malware masquerading as a Windows component, not evidence that Microsoft’s legitimate WerFault.exe was compromised.

A separate batch-based chain constructed .NET and Win32 API references dynamically, decoded an embedded Base64 payload, allocated executable memory, and launched it through a new thread. This avoided writing the decoded payload to disk.

Alert from the Protest Notary of the state of Goiás about the scam (Source : WatchGuard).

Researchers also recovered werdata.db, an encrypted file containing Donut x64 shellcode protected with Chaskey in counter mode.

WatchGuard Red Cell researcher Euler Neto investigated, three malware campaigns involving VBScript (VBS), revealing how cybercriminals combine phishing, obfuscated scripts, and legitimate Windows components.

Configuration checks, the string OVERLORD-SECURE-LOG, and network traffic connected the activity to Overlord RAT infrastructure at 191[.]96[.]225[.]125.

MSI variants used DLL side-loading, pairing malicious libraries with legitimate ngentask.exe or VLC executables.

Those samples contacted 45[.]158[.]8[.]213, illustrating how trusted applications can become execution hosts for attacker-controlled code.

Defender exclusion and curl or PowerShell execution in the batch file (Source : WatchGuard).

The Lampion campaign used financial-document phishing and ZIP attachments containing HTML lures that led victims toward malicious VBS files.

Neto found scripts inflated to approximately 5 MB despite containing roughly 5 KB of executable logic.

Related Acronis research documented a Portugal-focused Lampion operation in which 94.6% of detections occurred in Portugal.

Its chain used scheduled tasks, extensive script obfuscation, and a heavily padded DLL payload of approximately 750 MB.

Bitsight separately documented Lampion’s use of compromised email accounts, cloud-hosted stages, and ClickFix lures.

These similarities establish tactical overlap, but repeated references to the number seven do not independently prove shared operators across the campaigns.

The third campaign presented a Portuguese invoice-download page with a fake CAPTCHAthat delivered an ISO.

Fake page that distributes the malware (Source : WatchGuard).

Inside, an obfuscated VBS launched legitimate VMware vnetlib.exe alongside malicious newdev.dll through DLL side-loading.

The library decrypted an embedded Pascal DLL exposing RunAgent. Its functionality included single-instance enforcement, screenshot-resolution configuration, HKCU registry persistence, and bot-identifier generation.

Observed command-and-control traffic targeted 148[.]224[.]62[.]243:7777, retrying failed connections every three seconds.

The combined findings highlight investigation priorities: suspicious WER-named tasks, Defender exclusions, unexpected script-to-PowerShell execution, and trusted binaries loading adjacent DLLs.

Correlating these behaviors provides stronger investigative context than trusting filenames, application signatures, or cloud-hosting reputations alone.

Across these cases, the decisive pattern is not one malicious tool, but coordinated abuse of scripting, trusted execution paths, and persistence mechanisms to obscure compromise.

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