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CISO PostMortem: Broadcom 0-Day (CVE-2025-41244) Bypasses WAFs, Hits SaaS/Cloud. Millions of Attacks Logged. — by CyberDudeBivash

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

LinkedIn: ThreatWirecryptobivash.code.blog

0-DAY RCE • WAF BYPASS • HTTP REQUEST SMUGGLING • CVE-2025-41244

Situation: This is a CISO-level zero-day PostMortem. A CVSS 9.8 Critical flaw, CVE-2025-41244, in Broadcom-manufactured load balancers and WAFs is being *mass-exploited* in the wild. This is an HTTP Request Smuggling vulnerability that allows attackers to *bypass your WAF and perimeter security* to hit your backend services directly, leading to Remote Code Execution (RCE) and full data exfiltration from SaaS and Cloud platforms.

This is a decision-grade brief. Your Zero-Trust policy is failing because it *trusts* your WAF. In this attack, your WAF *is* the vulnerability. Attackers are “smuggling” malicious requests *inside* “clean” ones. Your SIEM is blind because the attack appears to come from your *own trusted load balancer*. We are dissecting the TTP and providing the Incident Response (IR) and Threat Hunting mandate.

TL;DR — A “WAF-killer” flaw (CVE-2025-41244) in Broadcom hardware is being exploited.

• The Flaw: An HTTP Request Smuggling (HRS) vulnerability. It “de-syncs” your frontend WAF and your backend server.
• The Impact: WAF Bypass, Cache Poisoning, Session Hijacking, and RCE on backend applications.
• The Threat: Mass exploitation by APTs and ransomware gangs to breach SaaS/Cloud environments. Millions of probes are active.
• Why Defenses Fail: Your WAF inspects the “harmless” outer request and *misses* the “malicious” smuggled inner request. Your SIEM/EDR sees the attack coming from your *own trusted WAF IP*.
• THE ACTION: 1) PATCH NOW. This is an emergency, out-of-band patch. 2) HUNT. You *must* assume you are breached. Hunt for anomalous logs *from your load balancer’s IP*. 3) HARDEN. Enable HTTP/2 on your backend.

Contents

1. Phase 1: The “WAF-Killer” Exploit (How HTTP Request Smuggling Works)
2. Phase 2: The Kill Chain (From “Smuggled” Request to Backend RCE)
3. Phase 3: PostMortem – Why Your SIEM, EDR, and ZTNA Failed
4. The CISO Mandate: The “Hunt, Harden, Respond” Plan
5. Tools We Recommend (Partner Links)
6. CyberDudeBivash Services & Apps
7. FAQ

Phase 1: The “WAF-Killer” Exploit (How HTTP Request Smuggling Works)

To understand why this is a CISO-level crisis, you must understand this TTP. HTTP Request Smuggling (HRS) is not a “simple” flaw like SQLi. It is an *architectural* flaw that exploits a “desynchronization” between your frontend (the Broadcom load balancer/WAF) and your backend (your web/app server).

Here is the CISO-level breakdown:

1. A user’s HTTP request arrives. It must pass through two devices: your Frontend (WAF) and your Backend (Server).
2. To handle requests, both must agree on “where one request ends and the next one begins.” They use `Content-Length` (CL) or `Transfer-Encoding` (TE) headers for this.
3. The Flaw (The “Desync”): The attacker sends *one* “magic packet” that contains *both* headers. The Broadcom WAF (Frontend) only sees the `Content-Length` header. The backend server (e.g., Apache, Nginx) only sees the `Transfer-Encoding` header.
4. This “de-syncs” their parsers. The WAF sees *one harmless request*. The backend server sees *two* requests: the harmless one, and a *second, malicious* one “smuggled” in the body.

The result: The attacker’s malicious payload (`POST /admin/delete_user…`) completely bypasses your multi-million dollar WAF. Your perimeter is now useless. This is a “golden key” exploit for any SaaS or Cloud platform.

Phase 2: The Kill Chain (From “Smuggled” Request to Backend RCE)

This zero-day is the *initial access* and *WAF bypass* all in one. APTs and ransomware gangs are using it for a devastating kill chain.

Stage 1: Initial Access (The Smuggled Request)

The attacker sends their “magic packet” to your public-facing IP. Your vulnerable Broadcom appliance receives it.
Frontend WAF sees: `POST /login HTTP/1.1`… `Content-Length: 150`… `(harmless body)`…
Backend Server sees: `POST /login HTTP/1.1`… `Transfer-Encoding: chunked`… `(harmless body)`… *and*… `POST /api/upload.php HTTP/1.1`… `(malicious web shell)`

Stage 2: WAF Bypass & RCE

Your WAF inspects the “harmless” `/login` request, finds no SQLi, and marks it “CLEAN.” It forwards the *full, poisoned* request to the backend. The backend server *executes* the “smuggled” `/api/upload.php` request.
The attacker has now uploaded a web shell. They have Remote Code Execution (RCE) *inside* your “secure” perimeter.

Stage 3: Persistence, Lateral Movement, & Exfiltration

The attacker is now “in.” From this web shell (running as `www-data` or `apache`), they will:

1. Run a Local Privilege Escalation (LPE) exploit (like the recent Linux kernel flaw) to become `root`.
2. Use `root` to *kill your EDR agent* (e.g., `systemctl stop kaspersky-edr`).
3. Dump all credentials, pivot to your database, and begin “low-and-slow” data exfiltration of your *entire* SaaS customer database (the “4TB Question”).
4. After the data is gone, they deploy ransomware to cover their tracks.

Phase 3: PostMortem – Why Your SIEM, EDR, and ZTNA Failed

This TTP is a kill-shot to “lazy” Zero-Trust architectures. Your security stack was blind.

1. Your WAF Failed (It was the Target)

Your WAF *was* the vulnerability. It was “de-synced.” It was not just blind; it was the *unwitting accomplice* that “smuggled” the attack past your perimeter.

2. Your SIEM/Logs Failed (The “Trusted” IP)

This is the *critical* failure. Your backend web server *did* log the attack (`POST /api/upload.php`). But what was the *source IP* in that log? It was the *internal IP of your load balancer*.
Your SIEM saw thousands of malicious requests coming from a *trusted internal IP* and likely *ignored* them, assuming it was “health check” traffic or “benign noise.” Your Zero-Trust policy *explicitly trusts* your load balancer!

3. Your EDR Failed (It Was Too Late)

Your EDR *might* have seen the *post-exploit* behavior (e.g., `apache2 -> /bin/bash`). But by then, the *web shell is already planted*. A sophisticated attacker will use a fileless, in-memory web shell that your EDR’s static scanner will *never* find.
You cannot rely on EDR to stop this. You *must* have a *human* team hunting for the *behavioral anomalies*.

The CISO Mandate: You MUST have a 24/7 MDR.
An automated EDR is just a “noise generator.” You need a Managed Detection & Response (MDR) service. Our 24/7 CyberDudeBivash SecOps team is trained to hunt for *these specific TTPs*.

We see `apache2` spawning `bash` and call it a “P1 Incident.” We see 10,000 requests from your *load balancer IP* in one second and call it an “HRS Attack.” We provide the *human* analysis your AI-powered tools are missing.
Explore Our 24/7 MDR Service →

The CISO Mandate: The “Hunt, Harden, Respond” Plan

This is an active CISA KEV alert. This is an Incident Response emergency. Drop everything.

Step 1: PATCH NOW (Hours 0-1)

This is your only priority. Call your Broadcom/VMware vendor.

1. Read the Security Advisory for CVE-2025-41244.
2. Apply the emergency patch/firmware update to *all* vulnerable load balancers and WAFs.
3. This will likely require a *reboot* and a maintenance window. The CISO mandate is: “The maintenance window is *now*.”

Step 2: HUNT (Hours 1-24)

You *must assume you are already breached*. The exploit is public and being mass-scanned. Patching *now* locks the door, but the attacker is *already inside*. Your SOC or MDR provider must *immediately* start threat hunting.

• Hunt for the IOC (The Log): This is your #1 indicator. Get your logs from your *backend servers* (`apache`, `nginx`, `iis`). Hunt for *any* request that:
  • Originates from your *load balancer’s IP*.
  • Contains a `POST` request to an anomalous endpoint (like `/upload.php`, `/cmd.jsp`, `/admin/`).
  • Contains `powershell.exe`, `bash`, or other shell commands.
• Hunt for the TTP (The File): Scan *all* your web directories for new/suspicious `.php`, `.jsp`, or `.aspx` files (web shells).

This is an active Incident Response (IR) scenario.
If you find *any* of this, you are breached. Call our 24/7 Incident Response hotline. Our digital forensics team will find the web shell, trace the attacker’s lateral movement, and eradicate them from your network.

Step 3: HARDEN (The *Real* Fix)

A patch is not a strategy.

• Enable HTTP/2: The HTTP/2 protocol is *not* vulnerable to this class of smuggling. Mandate end-to-end HTTP/2 from your frontend to your backend.
• Normalize Requests: Use a *modern* cloud WAF (like Alibaba Cloud’s) that *normalizes* all ambiguous requests *before* passing them to the backend.
• Test It: You *must* verify this. A simple patch is not enough. You need a human-led VAPT / Red Team to *specifically* test for HRS vulnerabilities.

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 *last line of defense*. The WAF *will* fail. Your EDR is the *only* tool that can see the *post-exploit* web shell behavior (`apache -> bash`).Alibaba Cloud (WAF)
The *best* mitigation. A cloud-native WAF is built to *normalize* HTTP requests and kill HRS attacks. Ditch the legacy hardware.Edureka — Network Security Training
Train your team *now* on Advanced Web Attacks (HRS), Threat Hunting, and Incident Response.

AliExpress (Hardware Keys)
Protect your *admin accounts*. Use FIDO2/YubiKey for all privileged access to your WAF, EDR, and cloud consoles.TurboVPN
Your WAF’s `/admin` panel should *never* be on the public internet. *Only* accessible via a trusted admin VPN.Rewardful
Run a bug bounty program. Pay white-hats to find these simple, critical flaws before attackers do.

CyberDudeBivash Services & Apps

We don’t just report on these threats. We hunt them. We are the expert team you call when your “trusted” perimeter fails.

• Emergency Incident Response (IR): Our 24/7 team will deploy *today* to hunt for the web shell and trace the APT’s lateral movement.
• Adversary Simulation (Red Team): Our flagship service. We will *simulate* this *exact* HTTP Request Smuggling TTP to prove if your WAF is *really* secure.
• Managed Detection & Response (MDR): Our 24/7 SOC team becomes your “human sensor,” watching your *backend* logs for the anomalies your SIEM misses.
• PhishRadar AI — Stops the phishing attacks that *initiate* other breaches.
• SessionShield — Protects your *admin* sessions, so even if an attacker gets `SYSTEM`, we detect their anomalous *session* behavior.

Book 24/7 Incident ResponseBook an Adversary Simulation (Red Team)Subscribe to ThreatWire

FAQ

Q: What is HTTP Request Smuggling (HRS)?
A: It’s an attack that exploits a “de-sync” between your frontend WAF and your backend server. The attacker “smuggles” a malicious 2nd request inside a “harmless” 1st request. The WAF *only inspects the 1st request*, allowing the 2nd (malicious) one to pass through undetected.

Q: We use a *cloud* WAF (e.g., Cloudflare/Akamai), not Broadcom. Are we safe?
A: You are safe from *this specific CVE*. You are *not* safe from the *TTP*. HRS flaws exist in *all* web stacks. You *must* have your application *tested* for HRS, or you are blind. (This is what our Red Team does).

Q: I’ve patched my Broadcom appliance. Am I safe?
A: You are safe from *new* attacks using this flaw. You are *not* safe if an attacker *already* breached you. You MUST complete “Step 2: Hunt for Compromise” or call our IR team to do it for you.

Q: How do I hunt for this?
A: This is the “4TB Question.” You *must* analyze your *backend web server logs*. Look for *any* requests that originate from your *load balancer’s IP* that look malicious (e.g., `cmd.exe`, `powershell.exe`, `/admin/` access). This is the #1 IOC. If you don’t have this telemetry, you *must* deploy a Kaspersky EDR agent on the backend server *today*.

Next Reads

• [Related Post: The 5 “Fileless” Attack TTPs Your EDR is Missing]
• Daily CVEs & Threat Intel — CyberBivash
• CyberDudeBivash Apps & Services Hub

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