From OneNote to RansomNote: A .one Attachment to Nokoyawa Ransomware
A phishing email carrying a malicious OneNote (.one) attachment delivered the IcedID loader, which beaconed quietly for weeks before the operator launched Cobalt Strike, enumerated Active Directory with AdFind, installed AnyDesk for redundancy, moved laterally over RDP, exfiltrated data over SFTP, and deployed Nokoyawa ransomware on the backup and file servers. Reconstruct the full kill chain from SIEM, endpoint XDR, and perimeter firewall telemetry, and classify the key ATT&CK techniques.
Start this operation
Investigation Tasks
Complete each task by investigating alerts and submitting your findings.
Incident brief
0Orient yourself before pivoting into the data. This is a no-answer briefing checkpoint.
Find the initial lure
35Everything traces back to one file a user opened. Recover the file-level indicator for the attachment that started the intrusion.
Classify the file-type deception
30The loader was hidden in plain sight by lying about what kind of file it was. Identify the MITRE ATT&CK sub-technique.
Classify the loader's persistence
30The loader made sure it would survive a reboot. Identify the MITRE ATT&CK sub-technique for how it persisted.
Separate hands-on control from the loader
35After weeks of quiet, the operator switched to a second command channel for interactive control. Identify its external IP.
Trace the lateral movement
35The operator reached a server they should never have touched from a workstation. Identify the host they pivoted into first.
Separate the exfiltration from the command channels
35Before encryption the operator stole data on its own infrastructure. Identify the external IP that received it.
Recover the encryptor indicator
35Pin down the file-level indicator for the ransomware so it can be hunted. Provide the SHA-256 of the encryptor binary.
8 tasks · 235 points total
Training Tools
Skills You'll Build
Requires foundational alert triage skills. Multiple data sources to correlate.
Prerequisites
- Basic understanding of security alerts
- Familiarity with SIEM concepts
- Familiarity with XDR concepts
- Familiarity with Firewall concepts
Ready to investigate?
More Operations
View allThe Template That Read the Disk
The file-transfer portal that Tideglow Logistics' partners upload to spent a morning returning host files it was never meant to publish, and finished it running an administrator session nobody had logged into. The root cause is CVE-2024-4040 in CrushFTP 10.6.0. Walk the access logs and firewall traffic step by step to trace how a client holding no credentials turned a request parameter into a read of the host, and that read into a takeover.
OneNote Attachment to RAT: A Guided First Investigation
A logistics contracts employee at Glacierline Freight opens an attachment that arrived in her inbox and clicks a button inside it. Minutes later her workstation is running something that appears on no software inventory and is talking to a host that no business process uses. Walk the email gateway records, the file artifacts and the endpoint process tree one step at a time, and work out for yourself which message carried the delivery, what landed on disk, and what ran.
Hijacked Discord Invite to ClickFix Loader: Tracing the Lure
A finance analyst at Halcyon Wealth Partners followed a recycled Discord invite that quietly redirected the browser to a fake verification page. They did what the page asked, and inside the hour the workstation was running a remote-access trojan alongside an info-stealer that shipped browser data straight out of the building. Walk the proxy, endpoint and firewall evidence step by step to trace the lure, the loader, the C2 beacon and the data theft.