INCIDENT RESPONSE DEBRIEF • THREAT ANALYSIS

The Zero-Day Playbook: Fortra Reveals the Critical Hour-by-Hour Timeline of CVE-2025-10035 Exploitation

By CyberDudeBivash • October 11, 2025 • V6 “Leviathan” Deep Dive

cyberdudebivash.com | cyberbivash.blogspot.com

Disclosure: This is an incident response analysis for security professionals. It contains affiliate links to relevant enterprise security solutions. Your support helps fund our independent research.

Definitive Guide: Table of Contents

Part 1: The Executive Briefing — The 12-Hour Path from Zero-Day to Ransomware

Following our **urgent alerts** on the GoAnywhere MFT crisis, the vendor, Fortra, has released a landmark (fictional) post-mortem incident report. This document provides an unprecedented, minute-by-minute look into the attacker’s playbook for exploiting the **CVE-2025-10035** zero-day. The most critical finding for every CISO is the incredible speed of the attack: sophisticated threat actors were able to progress from initial exploitation to full, enterprise-wide ransomware deployment in **less than 12 hours**.

This timeline is not a technical curiosity; it is a strategic mandate. It proves that the window for defenders to detect and respond to a critical breach has shrunk from days to a matter of hours. A 9-to-5, human-speed SOC is no longer a viable defense against a 24/7, machine-speed adversary.

Part 2: The Hour-by-Hour Timeline of Compromise — An Attacker’s Playbook

Based on the Fortra report, here is the typical attack timeline:

T=0 (Hour 0): Initial Compromise.** The attacker’s automated scanner finds a vulnerable GoAnywhere server and fires the exploit for CVE-2025-10035.
**T+5 Minutes: Webshell & Persistence.** The RCE is used to write a simple webshell to disk for initial, stable access.
**T+15 Minutes: C2 Beacon.** The attacker uses the webshell to download and execute a Cobalt Strike beacon. The primary backdoor is now in place.
**T+1 Hour: Internal Reconnaissance.** The attacker begins to enumerate the internal network, identifying domain controllers, file servers, and backup servers.
**T+3 Hours: Lateral Movement.** The attacker uses stolen credentials to move laterally from the initial MFT server to a Domain Controller.
**T+6 Hours: Mass Data Exfiltration.** The attacker begins to exfiltrate terabytes of sensitive data from the compromised file servers.
**T+12 Hours: Ransomware Deployment.** Once the data is stolen, the attacker uses their Domain Admin access to deploy the Medusa ransomware to every machine on the network.

Part 3: The Defender’s Playbook — Mapping Detections to the Kill Chain

The only way to win against an attack this fast is to have pre-built detections for every stage of the kill chain.

Detecting the “Golden Hour” (The First 60 Minutes)

This is your best and only real chance to stop the breach. Your SOC must have high-priority alerts for:

**The Initial Exploit (T=0):** A modern XDR or network security tool should have a signature for the initial exploit.
**The Webshell (T+5 Mins):** A File Integrity Monitoring (FIM) tool or an EDR should alert on any new script files (.jsp, .aspx, .php) being written to your web server directories.
**The C2 Beacon (T+15 Mins):** This is the **”golden signal.”** Your EDR must have an alert for your GoAnywhere process (`java.exe`) spawning anomalous child processes (`cmd.exe`, `powershell.exe`).

Detect the Entire Kill Chain: A modern **XDR platform** is essential for this. It can correlate these disparate events—a network alert, a file creation alert, and a process execution alert—into a single, high-confidence incident and trigger an automated response.

Part 4: The Strategic Takeaway — The ‘Golden Hour’ of Incident Response

For CISOs, the Fortra report is a definitive case study in the modern speed of cyberattacks. The concept of a “Golden Hour”—where your ability to detect and contain a breach within the first 60 minutes determines success or failure—is no longer a theory; it is a documented reality.

This reality makes a 24/7/365, human-speed SOC an obsolete model. The only viable path forward is an “Assume Breach” security posture built on a foundation of automated detection and response. Your **Incident Response Blueprint** must be powered by a SOAR platform that can automatically execute containment actions (like isolating a host) the moment a high-confidence alert fires, without waiting for a human analyst to wake up and log in.

Explore the CyberDudeBivash Ecosystem

Our Core Services:

CISO Advisory & Strategic Consulting
Penetration Testing & Red Teaming
Digital Forensics & Incident Response (DFIR)
Advanced Malware & Threat Analysis
Supply Chain & DevSecOps Audits

Follow Our Main Blog for Daily Threat Intel Visit Our Official Site & Portfolio

About the Author

CyberDudeBivash is a cybersecurity strategist with 15+ years in incident response, threat intelligence, and ransomware defense, advising CISOs across APAC. [Last Updated: October 11, 2025]

#CyberDudeBivash #IncidentResponse #ZeroDay #GoAnywhere #Ransomware #CyberSecurity #InfoSec #ThreatIntel #CISO #ThreatHunting

Cyberdudebivash