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CISO Briefing: How to Build a $100,000-Level Ransomware Detection System with Wazuh (And the 5 Mistakes to Avoid) — by CyberDudeBivash

By CyberDudeBivash · 01 Nov 2025 · cyberdudebivash.com · Intel on cyberbivash.blogspot.com

LinkedIn: ThreatWire cryptobivash.code.blog

RANSOMWARE • WAZUH • SIEM • THREAT HUNTING • EDR

Situation: As a CISO, you’re quoted $100,000+ for a “Next-Gen” Ransomware Detection platform. But your *real* problem is “alert fatigue” and a slow MTTR (Mean Time to Respond). The “costly” tools are just SIEMs with a fancy dashboard. Wazuh, a *free, open-source* platform, can deliver 90% of that value *if* you stop using it like an AV and start using it like a Threat Hunting tool.

This is a decision-grade CISO brief. This is the *playbook* to turn your “noisy” Wazuh deployment into a silent, elite Ransomware-hunting machine. We will show you how to *stop* hunting for “malware.exe” (Mistake #1) and start hunting for *behavior*—like fileless malware, EDR bypass TTPs, and covert data exfiltration.

TL;DR — Stop paying $100k for a “ransomware” tool. Build a *better* one with Wazuh.

The “$100k” Lie: Expensive tools are just SIEMs that *react* to *known* signatures. They *will* miss 0-day and fileless attacks.
The “Wazuh” Win: Wazuh is a *proactive* Threat Hunting platform. It gives you the raw *telemetry* (FIM, process logs, registry keys) to hunt for *behavior*.
The “5 Mistakes” to Avoid:
1. Hunting *Signatures*, not *Behaviors*.
2. Ignoring Fileless (LotL) Attacks (`powershell.exe`).
3. Not Monitoring for Data Exfiltration (the *real* attack).
4. Having “Noisy” Alerts (alert fatigue).
5. Having no *Automated Response* (slow MTTR).
THE ACTION: This post is the *playbook*. We will give you the *exact* TTPs and Wazuh rule stubs to hunt for the *real* ransomware kill chain.

Detection Playbook Factbox: Ransomware Kill Chain

Kill Chain Phase	Attacker TTP	Wazuh Module (The “Fix”)
Initial Access	Phishing / LNK Exploit	Process Monitoring (Sysmon)
Defense Evasion	“Living off the Land” (LotL)	Command/Process Monitoring
Discovery	`whoami`, `net user`, `ipconfig`	Command/Process Monitoring
Data Exfiltration	`rclone`, DNS Tunneling, C2	Network/DNS Monitoring
Impact	`vssadmin delete shadows`	Command Monitoring + FIM

RansomwareEDR Bypass TTPThreat HuntingContents

Phase 1: The 5 Mistakes That Make Your SIEM “Useless”

As a CISO, I see this in 9/10 Incident Response engagements. A company *has* a SIEM (like Wazuh or Splunk), but they *still* get breached. Why? Because the tool is “on,” but it’s not “tuned.” They are making these 5 critical mistakes.

Mistake #1: Hunting Signatures, Not Behaviors

Your SOC is looking for “known-bad” file hashes (signatures). This is *useless*. APTs and Ransomware gangs (like UNC6384) compile *new, unique* malware for *every* victim. There is no signature. You *must* hunt for the *behavior*: `powershell.exe -e …` (fileless attack).

Mistake #2: Ignoring “Living off the Land” (LotL)

Your SOC has *whitelisted* `powershell.exe`, `wmic.exe`, `bitsadmin.exe`, and `cmd.exe`. You *have* to, right? Your admins use them. This is the EDR Bypass. Attackers *only* use these “trusted” tools. Your SOC *must* hunt for *anomalous* use of *trusted* tools (e.g., `powershell.exe` run by your `www-data` web server).

Mistake #3: Ignoring Data Exfiltration (The Real Breach)

Your SOC is focused on the “boom” (the encryption). You *missed* the “sneak” (the data exfiltration). The “4TB Question” is: Did you see the attacker *stealing* your data *before* the ransomware? You must hunt for *covert C2 channels* like DNS Tunneling.

Mistake #4: “Alert Fatigue” (A “Noisy” SIEM is a “Useless” SIEM)

Your SIEM generates 10,000 “low” alerts. Your 9-to-5 SOC team is burned out. The *real* attack (a “medium” alert: “PowerShell spawned by Word”) gets *missed* in the noise. You must *tune* your SIEM to only alert on high-fidelity, *chained* TTPs.

Mistake #5: No Automated Response (Slow MTTR)

Your SOC *sees* the “Ransomware” alert… at 3:00 AM. They create a ticket. The analyst sees it at 9:00 AM. By then, your company is encrypted. Your Mean Time to Respond (MTTR) is 6 hours. The attacker’s “Time to Encrypt” is 6 *minutes*. You *must* have an *automated* response (an “Active Response” in Wazuh) to *instantly* “jail” the infected endpoint.

Phase 2: The “CyberDudeBivash” Wazuh Playbook (Hunting TTPs)

Here is the playbook to fix this. We will use Wazuh’s *built-in* modules (FIM, Sysmon, and Active Response) to hunt for the *behaviors* of the ransomware kill chain.

Kill Chain Detection 1: Initial Access (The LNK)

The attack starts with a `.LNK` file in a `.ZIP`. We can’t scan the ZIP, but we can *see* what the LNK does.

TTP: `explorer.exe` (User click) → `powershell.exe -e …` (obfuscated, fileless command).
Wazuh Module: Sysmon (Event ID 1) + Custom Rules.
The “Hunt”: You need a Wazuh rule that alerts on *any* process spawning `powershell.exe` with an *encoded* or *obfuscated* command.

<!-- Wazuh Rule Stub (local_rules.xml) -->
<rule id="100101" level="12">
  <if_sid>61603</if_sid> <!-- Sysmon - Process Create -->
  <field name="win.eventdata.image">powershell.exe</field>
  <match_any>
    <field name="win.eventdata.commandLine">-e |</field>
    <field name="win.eventdata.commandLine">-enc |</field>
    <field name="win.eventdata.commandLine">-EncodedCommand</field>
  </match_any>
  <description>CyberDudeBivash TTP Hunt: High-priority "Fileless" (Obfuscated PowerShell) command detected.</description>
  <group>pci_dss_11.4,gdpr_IV_35.7.d,hipaa_164.308.a.1,nist_800_53_SI.4,tsc_CC7.2,tsc_CC7.3,</group>
</rule>

Kill Chain Detection 2: Defense Evasion (The LotL)

The attacker is now *in*. They are “Living off the Land.” You *must* hunt for this *recon* behavior.

TTP: `powershell.exe` → `whoami.exe`, `net.exe`, `ipconfig.exe`
Wazuh Module: Sysmon (Event ID 1) + Custom Rules.
The “Hunt”: We create a “parent-child” rule. We *don’t* care about `whoami.exe`. We *do* care if it’s spawned by `powershell.exe`.

<!-- Wazuh Rule Stub (local_rules.xml) -->
<rule id="100102" level="10">
  <if_sid>61603</if_sid> <!-- Sysmon - Process Create -->
  <field name="win.eventdata.parentImage">powershell.exe|cmd.exe|java.exe|apache2.exe</field>
  <field name="win.eventdata.image">whoami.exe|net.exe|ipconfig.exe|systeminfo.exe</field>
  <description>CyberDudeBivash TTP Hunt: "Living off the Land" (LotL) recon detected. A trusted process is running recon commands.</description>
  <group>pci_dss_11.4,gdpr_IV_35.7.d,hipaa_164.308.a.1,nist_800_53_SI.4,tsc_CC7.2,tsc_CC7.3,</group>
</rule>

Kill Chain Detection 3: Impact (The “Shadow Delete”)

This is the *last step* before encryption. The attacker *deletes your backups*.

TTP: `vssadmin.exe delete shadows /all` (Deletes Volume Shadow Copies).
Wazuh Module: Sysmon (Event ID 1) + Command Monitoring.
The “Hunt”: This command is *never* “noise.” This is a 100% “hands-on-keyboard” ransomware attack.

<!-- Wazuh Rule Stub (local_rules.xml) -->
<rule id="100103" level="15">
  <if_sid>61603</if_sid> <!-- Sysmon - Process Create -->
  <field name="win.eventdata.image">vssadmin.exe</field>
  <field name="win.eventdata.commandLine">delete shadows</field>
  <description>CyberDudeBivash TTP Hunt: CRITICAL RANSOMWARE. Volume Shadow Copy deletion detected.</description>
  <group>pci_dss_11.4,gdpr_IV_35.7.d,hipaa_164.308.a.1,nist_800_53_SI.4,tsc_CC7.2,tsc_CC7.3,</group>
</rule>

Phase 3: Automated Response (The “1-Minute” MTTR)

Now, we *fix* Mistake #5. We *automate* the response. In your Wazuh `ossec.conf`:

<command>
  <name>host-isolate</name>
  <executable>firewall-block.sh</executable>
  <timeout_allowed>no</timeout_allowed>
</command>

<active-response>
  <command>host-isolate</command>
  <rules_id>100103</rules_id> <!-- Trigger on our "Shadow Delete" rule -->
  <timeout>600</timeout>
</active-response>

What does this do? The *instant* Wazuh sees the “Shadow Delete” TTP, it *automatically* runs the `host-isolate` script on the endpoint. This script *immediately* adds a firewall rule to *block all network traffic*.

Your MTTR (Mean Time to Respond) just went from 6 *hours* to 6 *seconds*. The ransomware payload *cannot be downloaded*. The C2 beacon is *cut off*. You have *contained* the breach, automatically, for $0.

Detection Rule Validation (Blue-Team)

You *must* test your new rules. This is your Red Team validation.

Go to a *sandboxed* test machine with the Wazuh agent and *run the attack TTPs*.

# Test 1: LotL Recon
powershell.exe -c "whoami"

# Test 2: Fileless
powershell.exe -e JABjAGgAbwBjAGsAZQAgACIAIgA=

# Test 3: Ransomware Impact
vssadmin.exe delete shadows /all /quiet

Now, go to your Wazuh dashboard. Did you get a Level 10+ alert? Did your “Active Response” fire? If “yes,” your new $100k-level detection system is working. If “no,” your rules are misconfigured.

Recommended by CyberDudeBivash (Partner Links)

Wazuh is a *sensor*. You *still* need a layered defense. Here’s our vetted stack.

Kaspersky EDR
Wazuh is good, but Kaspersky EDR is *great*. It has these *behavioral* TTPs built-in, providing a powerful “first line” of defense.Edureka — Threat Hunting Training
Your SOC team can’t find what they don’t know. Train them *now* on Wazuh Rule Writing and Threat Hunting.Alibaba Cloud (VPC/SEG)
This is *how* you build the “Firewall Jails” (Network Segmentation) to *contain* the ransomware blast radius.

AliExpress (Hardware Keys)
*Mandate* this for all Domain Admins. Get FIDO2/YubiKey-compatible keys. They stop the *initial phish* from succeeding.TurboVPN
Secure your admin access. Your RDP/SSH access for *your admins* should be locked down.Rewardful
Run a bug bounty program. Pay white-hats to find flaws *before* APTs do.

CyberDudeBivash Services & Apps

Wazuh is a powerful *sensor*. It is not a *solution*. It requires a 24/7 team of *expert human hunters* to tune it and watch it. This is the “MDR” gap.

Managed Detection & Response (MDR): This is the *solution*. Our 24/7 SOC team becomes your Wazuh Threat Hunters. We tune the rules, hunt the “noise” for *real* TTPs, and *respond* in minutes.
Adversary Simulation (Red Team): This is the *proof*. We will *simulate* this exact “LotL” kill chain to test if your *new* Wazuh rules *actually* fire.
Emergency Incident Response (IR): You found `vssadmin.exe`? Call us. Our 24/7 team will hunt the attacker and eradicate them.
PhishRadar AI — Stops the phishing attacks that *initiate* the breach.
SessionShield — Protects your *admin* sessions, so even if the attacker gets `SYSTEM`, we detect their anomalous *session* behavior.

Explore 24/7 MDR for Wazuh Book an Adversary Simulation (Red Team)Subscribe to ThreatWire

FAQ

Q: What is Wazuh?
A: It’s a free, open-source SIEM (Security Information and Event Management) and XDR platform. It’s a *sensor* (agent) you install on your endpoints that collects logs (FIM, process, registry, network) and an *engine* (server) that analyzes them.

Q: Is Wazuh *better* than a $100k tool like CrowdStrike?
A: It’s *different*. CrowdStrike (an EDR) has *better* out-of-the-box *prevention* and *AI-blocking*. Wazuh (a SIEM/XDR) gives you *better* raw *telemetry* and *customization* for *hunting*. The *best* solution is both: a “best-in-breed” EDR (like Kaspersky) *plus* a 24/7 human MDR team.

Q: What is “Fileless Malware” or “LotL”?
A: “Living off the Land.” It’s an attack where the adversary uses *your own legitimate, trusted software* against you. They don’t use “malware.exe.” They use `powershell.exe`, `wmic.exe`, or `java.exe`. It’s *designed* to be *invisible* to EDRs that “whitelist” trusted processes.

Q: What’s the #1 action to take *today*?
A: Enable Behavioral Hunting. You *must* assume your EDR will be bypassed. You *must* have a *human* MDR team (either internal or ours) that is *paid* to hunt for the “TTPs” (like `java.exe -> powershell.exe`), not just “alerts.”

Timeline & Credits

This “Ransomware TTP” (LotL, EDR Bypass, Fileless) is the *standard operating procedure* for APT-level ransomware groups in 2025.
Credit: This playbook is a synthesis of Incident Response engagements and TTPs seen in the wild by the CyberDudeBivash threat hunting team.

References

Affiliate Disclosure: We may earn commissions from partner links at no extra cost to you. These are tools we use and trust. Opinions are independent.

CyberDudeBivash — Global Cybersecurity Apps, Services & Threat Intelligence.

cyberdudebivash.com · cyberbivash.blogspot.com · cryptobivash.code.blog

#Wazuh #Ransomware #SIEM #SOAR #MDR #ThreatHunting #EDRBypass #FilelessMalware #LotL #CyberDudeBivash #IncidentResponse #CISO #ROI

Cyberdudebivash

How to Build a $100,000-Level Ransomware Detection System with Wazuh (And the 5 Mistakes to Avoid)

CISO Briefing: How to Build a $100,000-Level Ransomware Detection System with Wazuh (And the 5 Mistakes to Avoid) — by CyberDudeBivash

Phase 1: The 5 Mistakes That Make Your SIEM “Useless”

Mistake #1: Hunting Signatures, Not Behaviors

Mistake #2: Ignoring “Living off the Land” (LotL)

Mistake #3: Ignoring Data Exfiltration (The Real Breach)

Mistake #4: “Alert Fatigue” (A “Noisy” SIEM is a “Useless” SIEM)

Mistake #5: No Automated Response (Slow MTTR)

Phase 2: The “CyberDudeBivash” Wazuh Playbook (Hunting TTPs)

Kill Chain Detection 1: Initial Access (The LNK)

Kill Chain Detection 2: Defense Evasion (The LotL)

Kill Chain Detection 3: Impact (The “Shadow Delete”)

Phase 3: Automated Response (The “1-Minute” MTTR)

Detection Rule Validation (Blue-Team)

Recommended by CyberDudeBivash (Partner Links)

CyberDudeBivash Services & Apps

FAQ

Timeline & Credits

References

Leave a comment Cancel reply

How to Build a $100,000-Level Ransomware Detection System with Wazuh (And the 5 Mistakes to Avoid)

CISO Briefing: How to Build a $100,000-Level Ransomware Detection System with Wazuh (And the 5 Mistakes to Avoid) — by CyberDudeBivash

Phase 1: The 5 Mistakes That Make Your SIEM “Useless”

Mistake #1: Hunting Signatures, Not Behaviors

Mistake #2: Ignoring “Living off the Land” (LotL)

Mistake #3: Ignoring Data Exfiltration (The *Real* Breach)

Mistake #4: “Alert Fatigue” (A “Noisy” SIEM is a “Useless” SIEM)

Mistake #5: No Automated Response (Slow MTTR)

Phase 2: The “CyberDudeBivash” Wazuh Playbook (Hunting TTPs)

Kill Chain Detection 1: Initial Access (The LNK)

Kill Chain Detection 2: Defense Evasion (The LotL)

Kill Chain Detection 3: Impact (The “Shadow Delete”)

Phase 3: Automated Response (The “1-Minute” MTTR)

Detection Rule Validation (Blue-Team)

Recommended by CyberDudeBivash (Partner Links)

CyberDudeBivash Services & Apps

FAQ

Timeline & Credits

References

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Mistake #3: Ignoring Data Exfiltration (The Real Breach)