Cyberdudebivash

Services: Threat Intel • MDR/XDR • CVE & Patch Orchestration • CSPM/CNAPP • DevSecOps & Secure App Development

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This report distills how a modern “Interlock”-branded ransomware operation would typically breach, escalate, laterally move, exfiltrate, and encrypt—mapped to ATT&CK—with concrete detections and response steps. Use it to prepare, detect early, and contain fast. Where public IOCs are unclear or fluid, we focus on behaviors that hold across builds/versions.

1) Executive Snapshot

• Threat class: Human-operated, double-extortion ransomware (data theft → encryption → leak pressure).
• Targets: Windows-first enterprise networks; opportunistic to mid-market; cloud file shares if reachable.
• Initial access: Stolen VPN creds, insecure RDP, phishing leading to info-stealers, public-facing app exploits (n-day/KEV).
• Living-off-the-land: Uses Cobalt/Sliver/Net tools* or native admin utilities (PowerShell, WMI, PsExec, RDP).
• Impact: Mass encryption of on-prem file servers, user shares, and reachable backups; business interruption + data-extortion site.

What stops it: Zero-Trust for admin access, EDR/XDR stop-rules on encryption behaviors, tight AD/backup hygiene, immutable offsite backups, and rapid IR.

2) MITRE ATT&CK Mapping (behavioral)

Treat the above as a hunting checklist—each row becomes a detection use case.

3) Likely Kill-Chain (Step-by-Step)

Step 1 — Access brokerage / foothold

• Compromised credentials (phished or from info-stealer logs) are tested against VPN/RDP/SSO.
• Vulnerable edge service exploited (e.g., unpatched web/remote admin).
  Defender task: block password reuse; enforce phishing-resistant MFA; keep all edge services in KEV-compliant patch state; geo/IP allowlists.

Step 2 — Post-exploitation staging

• Drop lightweight loader (native LOLBins or legit admin tools) → memory beacon to C2.
• Enumerate domain, high-value servers, backup infrastructure.
  Defender task: detect unknown beacons; watch for enumeration commands, net scans, AD queries from unusual hosts.

Step 3 — Priv-Esc + lateral movement

• UAC bypass or stolen admin token; jump using RDP/PsExec/WMI; spread to file servers and DC-adjacent hosts.
  Defender task: EDR block policy for PsExec and RDP lateral movement; detect psexecsvc creation and admin$ copy bursts.

Step 4 — Exfiltration prep

• Stage archives; exfil via Rclone/SFTP/WebDAV/cloud CLI to attacker-controlled storage.
  Defender task: monitor for new exes in %ProgramData%/%AppData%; egress allowlists; block cloud CLI tools on servers.

Step 5 — Impact

• Stop AV/backup services; delete shadow copies; push encryptor; run parallel encryption jobs across shares; drop ransom note.
  Defender task: stop-rules for mass file-touch/entropy spikes; lockdown on unexpected vssadmin delete shadows, wbadmin, bcdedit, wmic shadowcopy usage.

4) High-Fidelity Detections (drop-in)

A) Mass encryption behavior (EDR/XDR logic)

• Sudden >1,000 file writes/min with high entropy; many “rename to .<ext>” events; simultaneous activity across multiple shares.
• Tight rule: if process not in file-server allowlist AND touches >N files/minute with >M entropy → kill & isolate host.

B) Backup sabotage

index=windows EventCode IN (4688,1) CommandLine="*vssadmin*delete*shadows*" OR CommandLine="*wbadmin*delete*catalog*" OR CommandLine="*bcdedit*set*recoveryenabled*No*"
| stats count by host, user, parent_process, CommandLine

C) PsExec & lateral movement

index=windows (Image="*\\psexec.exe" OR Image="*\\psexesvc.exe") OR (CommandLine="*sc \\\\* create PSEXESVC*")
| stats count by dest, user, Image, CommandLine

D) Rclone / cloud exfil

index=windows Image="*\\rclone.exe" OR CommandLine="*rclone copy*" OR CommandLine="*rclone sync*"
| stats count by host, user, CommandLine

E) Shadow IT admin tools

index=windows (Image="*\\adfind.exe" OR Image="*\\bloodhound*") OR (CommandLine="*ldap*" AND CommandLine="*search*")
| stats count by host, user, Image, CommandLine

F) Suspicious service creation

index=windows EventCode=7045
| where like(ServiceName,"%psexesvc%") OR like(ImagePath,"%\\Users\\%") OR like(ImagePath,"%\\AppData\\%")

Convert to Sigma/Kusto as needed; tune with allowlists (backup servers will legitimately touch many files).

5) IR Playbook (first 48 hours)

Hour 0–2: Contain

• Isolate impacted hosts (EDR network containment).
• Disable compromised accounts & revoke tokens; rotate passwords of service & backup accounts.
• Block suspicious egress to newly observed IPs/domains.

Hour 2–8: Scope

• Pull process trees, service creations, scheduled tasks, and PowerShell transcripts.
• Hunt for exfil tools (Rclone/7zip/WinSCP) and staging dirs.
• Verify domain controllers integrity; inspect GPO for malicious startup scripts.

Hour 8–24: Eradicate

• Remove persistence (tasks, services, Run keys).
• Rebuild compromised servers from gold images; restore least privilege.
• Invalidate lateral movement paths (disable local admin re-use, reset KRBTGT if DC tampering suspected).

Hour 24–48: Recover

• Restore immutable backups after verifying no backdoor and no exfil foothold remains.
• Increase monitoring for 30 days (failed logons, new MFA devices, new OAuth consents, new scheduled tasks).
• Legal & comms: handle extortion note via incident response policy; involve counsel & law enforcement per jurisdiction.

6) Hardening That Works (repeatable wins)

• Identity: Phishing-resistant MFA (FIDO2), conditional access, disable legacy auth.
• Admin plane: Put RDP/SMB/Remote tools behind ZTNA/VPN; per-admin accounts; PAM for privileged elevation.
• EDR/XDR everywhere: Servers + workstations + DCs; tamper protection; block script interpreters launching from user profiles.
• Backups: 3-2-1 with immutable object-lock; routinely test restores; separate backup admin identity.
• AD Hygiene: Randomized local admin passwords (LAPS), tiered admin model, disable unused protocols, constrained delegation.
• Egress control: DNS + HTTP(S) allowlists from servers; block unknown cloud storage clients.
• Email/Web: Inline sandboxing, URL rewriting with time-of-click analysis; DMARC/DKIM/SPF enforced.
• Patch KEV: Prioritize edge & remote-management tooling; maintain a 7–14-day SLA for internet-facing services.

7) Ransom Note & Artifact Clues (generic)

• Note names often follow patterns like INTERLOCK-README.txt or HOW_TO_DECRYPT.txt.
• Extensions may be unique per build/campaign; do not rely on extension strings alone—hunt the behaviors above.
• Encryption usually precedes note write → the mass-file-touch signal is the earliest high-fidelity indicator.

Avoid chasing static IOCs—operators re-brand quickly. Ground your defenses in techniques and process behaviors.

8) Governance & Board Metrics

• MTTD/MTTR (endpoint + server + cloud).
• % of assets with EDR and tamper protection.
• % of backups immutable and offline; restore time validation.
• Patch SLA: KEV/internet-facing vulns within 7 days.
• Identity risk: % with FIDO2, conditional access coverage, PAM adoption.
• Lateral-movement risk: SMB signing enforced, RDP restricted, LAPS coverage.

9) CyberDudeBivash Services (we do the heavy lifting)

• Managed Detection & Response (MDR/XDR) — 24×7 monitoring + threat hunting
• Rapid CVE Triage & Patch Orchestration (24–48h SLAs)
• Zero-Trust & PAM deployments (RDP/VPN/remote tools off the internet)
• Immutable Backup & DR validation
• DevSecOps & Secure App Builds (SBOM, provenance, secrets)

Book a 30-min assessment → cyberdudebivash.com

Helpful tools (affiliate CTAs)

• Bitdefender GravityZone — stop ransomware behaviors & memory exploits on servers/workstations.
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• Aqua Security (CNAPP) — runtime policy for containers/K8s; guardrails against data exfil paths.
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• Snyk — scan code/containers/IaC; break the build on critical vulns.
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