Akira Ransomware: Full Kill Chain IR

CORP-FS-01 went dark overnight: files across the share were renamed to an unfamiliar extension and a ransom note appeared. The host that drove the encryption is corp-wks-102. Working from the impact backward, identify the executable that carried out the mass-encryption stage on that host.

Akira's operators pass their per-victim encryption key on the command line when they launch the encryptor. Having identified the payload on corp-wks-102, examine how it was invoked and recover the key value the operator supplied at runtime.

Before detonating the ransomware, the actor staged data for theft: a 14 GB transfer left CORP-FS-01 for an external host the night before encryption. On corp-wks-102 a burst of process activity preceded that transfer. Determine which legitimate-looking third-party utility the actor used to compress and bundle the data for exfiltration.

The operator needed an interactive channel to drive corp-wks-102 between initial access and impact. Shortly after the loader executed on the host, it began beaconing outbound to an external server. Identify the command-and-control destination the host was reaching out to.

From corp-wks-102 the actor pivoted toward the Domain Controller, installing a service on the remote host to run commands with SYSTEM privileges. Identify the service binary that carried out this remote-execution-based lateral movement.

To move freely and reach the Domain Controller, the actor needed privileges beyond the compromised user benjamin.smith. Investigate the net.exe activity on corp-wks-102 and the related account-management events to identify the high-privilege account the actor created and then reused to run the encryptor.

With a privileged account in hand, the actor went after Active Directory's credential store wholesale. Review the file-system activity in XDR on corp-wks-102 and identify the critical Active Directory database file the actor accessed to harvest every domain credential at once.

The privileged account did not appear from nowhere: earlier in the intrusion the actor harvested credentials directly from memory on corp-wks-102. Examine the process-execution chain and credential-access behavior in XDR to determine which signed system DLL was abused, alongside rundll32.exe, to dump LSASS memory.

Tracing further back toward the foothold: after the malicious installer ran on corp-wks-102, the actor sidestepped PowerShell controls by running their logic through a different scripting interpreter. Review the execution events that follow the msiexec.exe activity and identify the interpreter the actor used.

Closing the loop on root cause: the entire intrusion began with user benjamin.smith on corp-wks-102, where a file was dropped into a user temp directory after slipping past standard filtering. Analyze the XDR file-system artifacts for that user and identify the document written to disk as the initial-access foothold.