Cyber security

OnMouseMove-HtmlFile-PoC : Unpacking The HTML File Exploit In Russian APT Cyberattacks

PoC for onMouseMove HTML file used in the Russian APT Group campaign targeting Ukraine

The HTML File is included as an attachment in the phishing email, when the victim opens the html file and moves the mouse, this triggers the event handler attribute “onmousemove” which runs the Javascript, which further decodes the base64 encoded blob present in the HTML Body.

The base64 decoded blob consisting of further javascript routine which checks the Operating System and if this OS check is satisfied it drops the next stage i.e the ZIP archive decoded from another base64 encoded blob.

In the PoC, the ZIP archive has a text file 🙂 but in the ITW campaign it had a malicious Windows Shortcut File (.LNK) inside thr archive which remotely executed a HTA file via mshta.exe.

A Classic Anti-Sandbox Technique =)

Note: I’ve removed the usage of document.onmousemove event handler used in the ITW sample, as it was not necesary, adding the viewport height (100vh) covers the complete browser window.

Varshini

Varshini is a Cyber Security expert in Threat Analysis, Vulnerability Assessment, and Research. Passionate about staying ahead of emerging Threats and Technologies.

Recent Posts

git fetch vs git pull: How They Work and When to Use Each

Both git fetch and git pull talk to a remote repository, but they do very different things to your…

2 days ago

git cherry-pick Command: Apply Commits from Another Branch

Sometimes the change you need already exists, just on the wrong branch. A hotfix lands…

2 days ago

Best Email APIs for Secure Business Email: Why Developers Are Moving Beyond SMTP

Email is still one of the most important communication channels inside modern applications. Password resets,…

3 days ago

Nginx Commands in Linux: Start, Stop, Reload, Test, and Log

Nginx is a high-performance web server and reverse proxy trusted by some of the largest…

6 days ago

ufw Command in Linux: Manage Firewall Rules with Examples

ufw (Uncomplicated Firewall) sits on top of iptables (or nftables on newer systems) and replaces…

6 days ago

who Command in Linux: Show All Logged-In Users and Sessions

When you share a server with a team or investigate unexpected activity, the first question…

6 days ago