In a chilling display of modern cyber tactics, a new phishing campaign has emerged that delivers the DeerStealer malware using a deceptively harmless .LNK shortcut file. This attack leverages Microsoft’s own tools against users in a technique known as Living Off the Land (LOLBin)—and it’s a wake-up call for all organizations relying solely on conventional security layers.
What Makes This Threat So Dangerous?
At the center of this campaign is a file named “Report.lnk” — masquerading as a PDF document. Once clicked, it unleashes a multi-stage attack chain that cleverly hides its tracks and sidesteps detection tools.
The attackers use a legitimate Microsoft binary: mshta.exe, which normally runs HTML applications. But here, it’s being weaponized to run malicious scripts in a process that security tools typically trust.
This method is MITRE ATT&CK technique T1218.005 in action — abusing trusted tools like mshta.exe to execute harmful code while staying under the radar.
Breaking Down the Attack Chain
Let’s look at how this stealthy malware executes:
CopyEdit.lnk → mshta.exe → cmd.exe → PowerShell → DeerStealer
Here’s what’s happening at each step:
.LNKShortcut: Looks like a PDF icon. In reality, it contains embedded code to invokemshta.exe.mshta.exe: Executes obfuscated scripts encoded in Base64. These scripts are disguised to avoid detection.cmd.exeand PowerShell: Used to decode, reconstruct, and finally launch the real payload.- DeerStealer Payload: Installed silently in the AppData directory, while a real PDF opens as a decoy to distract the user.
All the while, logging is disabled, and no obvious signs are shown — making forensic investigation difficult.
Why This Technique Works So Well
Attackers are abusing “LOLBin” techniques — where Living Off the Land Binaries (i.e., built-in OS tools) are used for attacks instead of custom malware. Why?
- These tools are whitelisted by default
- They don’t raise red flags in many security systems
- Malware is assembled and executed only at runtime, evading static analysis
This means security tools focused only on signatures or blacklists are no match for this level of obfuscation.
Advanced Evasion Tactics
The attackers used:
- Wildcard path resolution to avoid specific detection rules
- Hex-to-ASCII decoding to dynamically build malicious scripts
- Obfuscated Base64 strings to carry payloads unseen
- Legitimate PDF files as distractions during infection
- Malicious domain:
tripplefury[.]com
All this amounts to a silent and surgical attack — one that can easily bypass legacy antivirus, basic endpoint protection, or insufficiently monitored systems.
Why You Should Care (Even If You’re Not the Target)
Even if you’re not currently targeted, campaigns like this signal a broader trend:
- Weaponized shortcuts are easy to deliver via phishing
- LOLBins are increasingly abused by cybercriminals
- Security blind spots still exist in PowerShell and CMD logging
- Many organizations still don’t monitor or restrict built-in Windows tools
If you’re relying on antivirus alone, you’re blind to runtime scripting attacks like these.
Finstein’s Security Awareness Tip
“Not all malware comes disguised in a .exe. Some come with a PDF icon and a shortcut to chaos.”
We urge teams to:
- ✅ Restrict or monitor the use of binaries like
mshta.exe,PowerShell, andcmd.exe - ✅ Deploy Endpoint Detection & Response (EDR) tools with behavioral analysis
- ✅ Enable detailed command-line and PowerShell logging
- ✅ Educate teams about suspicious file extensions, especially
.LNK
Final Thoughts
This isn’t just a clever malware drop — it’s a blueprint for future attacks. As attackers refine their methods using LOLBins and obfuscation, security hygiene must evolve too.
Startups, SMBs, and even enterprise security teams should revisit their assumptions about “safe” system files and known-good tools.
Awareness from Finstein
At Finstein, we don’t just detect threats — we prepare you for them.
Our cybersecurity frameworks are designed to:
- Harden endpoints against LOLBin misuse
- Detect malicious behaviors using behavioral telemetry
- Educate your team to recognize phishing entry points
- Ensure your PowerShell and system binary usage is audit-ready
Let’s move from reactive to proactive.
Praveen@Finstein.ai
+91 99400 16037
https://cyber.finstein.ai/
Don’t let a shortcut lead to your biggest security failure.
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Source :
1. https://cybersecuritynews.com/deerstealer-malware-delivered/
2.https://cybersectv.eu/deerstealer-malware-hides-in-lnk-file-using-lolbins/
