Recover readable logic from virtualized JavaScript you own or are authorized to assess, for malicious-script analysis, front-end security reviews and research.
JavaScript VM deobfuscation is the recovery of readable logic from JavaScript that an obfuscator has compiled into custom bytecode for a small interpreter shipped inside the script. Devirt analyzes virtualized JavaScript that you own or are authorized to assess, and it reports what it recovered with a coverage ledger that separates proven logic from everything that is not proven.
Family recognition is an intake decision, not a guarantee for every build. Custom behavior and multiple protection layers can require a separate assessment.
Virtualization replaces ordinary instructions with a custom interpreter. Devirt recovers meaningful operations and program structure so you can investigate behavior in your own tools.
The delivery pairs readable output with a full ledger for the agreed scope. Proven, runtime-dependent, unresolved, and permanently bounded units remain distinguishable, including units that were never virtualized.
See how the checks workCommon JavaScript deobfuscators work on the text of the code: they decode strings, rename variables and simplify expressions until the script reads normally again. That is enough for string encoding and name mangling.
Virtualized JavaScript is different. The protected functions no longer exist as JavaScript at all. What remains is a dispatcher that reads opcodes from a data blob and runs small handler functions, so the logic lives in the bytecode rather than in the code a deobfuscator rewrites. Obfuscators can also regenerate the interpreter for every build, so an instruction set worked out for one script does not carry over to the next.
JavaScript VM deobfuscation serves people who need to know what a virtualized script does and who are authorized to find out.
Devirt does not help bypass bot protection, anti-fraud systems or access controls, scrape websites or evade detection. JavaScript analysis is for code you own or are authorized to assess, and Devirt can decline a job and ask for the scope or the authorization to be clarified.
A JavaScript result explains what the virtualized code does, which interfaces it uses and which runtime conditions it depends on. Exact build and output eligibility are checked at intake, and every delivery includes the coverage ledger for the agreed scope.
A JavaScript result counts every unit in scope and places it in one of four states: proven, runtime-dependent, unresolved or permanently bounded. The four states add up to the declared total, so code that was not proven stays visible instead of dropping out of the count.
Virtualized JavaScript often depends on the page, the browser or data fetched at run time. Behavior that depends on those conditions is reported as runtime-dependent rather than presented as proven.
Every JavaScript VM job starts with a free assessment. Devirt reviews the script, states the scope, the estimated coverage and the timeline in a written offer, and nothing is charged unless you accept it.
Recognizing a JavaScript virtual machine at intake is an eligibility decision, not a guarantee for every build. Custom interpreters or several layers of obfuscation are reviewed in the assessment before any work is priced.
When part of a script cannot be proven, the result says so. It stays in the ledger as runtime-dependent, unresolved or permanently bounded, so you can decide whether the evidence answers your question.
One recovered program. Different ways to work with it. Inspect a teaching example, switch formats, and follow the link back to its evidence.
; Authored teaching VM, not vendor bytecode
00 LOAD32 r0, input.size
01 PUSH r0
02 PUSH 0x10
03 UGE
04 STORE p0
05 LOAD32 r1, input.magic
06 PUSH r1
07 PUSH 0x44565254
08 EQ
09 LOAD p0
10 AND
11 RET
#include <stdbool.h>
#include <stdint.h>
bool validate_record(uint32_t size, uint32_t magic) {
const uint32_t header_size = 16u;
const uint32_t expected_magic = 0x44565254u;
if (size < header_size) {
return false;
}
return magic == expected_magic;
}
Drag the divider to reveal the difference. Or choose a view above. Keyboard: arrow keys, Home and End.
Check the declared size. Check the type marker. Accept only when both checks pass.
Readable code explains the behavior. The ledger explains how far you can rely on it.
Original teaching material, not customer output. The IDA view illustrates a database's contents; it is not a downloadable .i64. No measured proof or service benchmark is claimed by these examples.
Every JavaScript VM job starts with the free assessment: Devirt reviews the script, estimates coverage and sends a written offer, and nothing is charged unless you accept it.
Start a free assessmentAn online deobfuscator rewrites the text of a script, which is often enough for encoded strings and renamed variables. Virtualized JavaScript keeps its logic in bytecode run by an embedded interpreter, so recovering it takes analysis of the interpreter and its instruction set. Devirt handles that case and reports its evidence.
Devirt analyzes only code you own or are authorized to assess, for purposes such as security research, malware analysis and interoperability. Unauthorized intrusion, evading security controls in an unauthorized environment, unlawful circumvention and redistribution without rights are prohibited under the acceptable use policy.
No. Devirt does not help bypass bot protection, anti-fraud systems or access controls, scrape websites or evade detection, and it declines jobs with that purpose.
Intake checks each build, and the free assessment states whether a script is in scope before any work is priced. Custom interpreters are assessed individually.
Your file is analyzed in an isolated environment and used only for the work you requested. Nothing is shared between customers and nothing is used for training. Input is deleted after completion and delivery, and released output stays available for 72 hours by default or 30 days on Team.
It stays in the coverage ledger as runtime-dependent, unresolved or permanently bounded instead of disappearing from the result. You see exactly what was proven and what was not.
Isolated analysis. No sharing between customers. No training on your upload. Your file is used only for the work you requested.
Read the data-handling policyIsolated processing
Not yet released
Recording the work
Input deletion follows delivery. This timeline shows the default 72-hour output window. Team outputs are kept for 30 days. Audit records have a separate 90-day window.
Policy illustration, not a live deletion certificate. Deletion is confirmed from provider receipts. Assessment inputs, unpaid jobs, and account/billing records have their own rules in the policy.
Start in your account. If your upload needs manual work, we review it and email you a written scope and quote before paid work begins.
Create an account, verify your email and upload your file. We review custom work and email your scope and quote.