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Fix self-defending obfuscated code hanging in Bun environments #1407

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Merged
sanex3339 merged 1 commit into from
Apr 17, 2026
Merged

Fix self-defending obfuscated code hanging in Bun environments #1407

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4 changes: 4 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
@@ -1,5 +1,9 @@
Change Log

v5.4.2
---
* Fixed obfuscated code hanging in Bun when `selfDefending` is enabled. Fixes https://github.com/javascript-obfuscator/javascript-obfuscator/issues/1404

v5.4.1
---
* Fixed `Utils.nodeRequire` causing `ReferenceError: require is not defined` in browser build by making it lazy-evaluated
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7 changes: 2 additions & 5 deletions package.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "javascript-obfuscator",
"version": "5.4.1",
"version": "5.4.2",
"description": "JavaScript obfuscator",
"keywords": [
"obfuscator",
Expand Down Expand Up @@ -132,10 +132,7 @@
"author": {
"name": "Timofei Kachalov"
},
"contributors": [
"Timofei Kachalov (https://github.com/sanex3339)",
"Dmitry Zamotkin (https://github.com/zamotkin)"
],
"contributors": ["Timofei Kachalov (https://github.com/sanex3339)", "Dmitry Zamotkin (https://github.com/zamotkin)"],
"license": "BSD-2-Clause",
"packageManager": "yarn@1.22.21+sha512.ca75da26c00327d26267ce33536e5790f18ebd53266796fbb664d2a4a5116308042dd8ee7003b276a20eace7d3c5561c3577bdd71bcb67071187af124779620a"
}
19 changes: 16 additions & 3 deletions src/custom-code-helpers/string-array/templates/string-array-calls-wrapper/AtobTemplate.ts
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Expand Up @@ -12,16 +12,29 @@ export function AtobTemplate(selfDefending: boolean): string {

let output = '';
let tempEncodedString = '';
${selfDefending ? 'let func = output + {atobFunctionName};' : ''}

${
selfDefending
? `
let func = output + {atobFunctionName};
let __ = ('' + function(){return 0;}).indexOf('\\n') !== -1;
`
: ''
}

for (
let bc = 0, bs, buffer, idx = 0;
buffer = input.charAt(idx++);
~buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer, bc++ % 4)
? output += ${((): string => {
const basePart: string = 'String.fromCharCode(255 & bs >> (-2 * bc & 6))';

return selfDefending ? `((func.charCodeAt(idx + 10) - 10 !== 0) ? ${basePart} : bc)` : basePart;
return selfDefending
? `
((__ || func.charCodeAt(idx + 10) - 10 !== 0)
? ${basePart}
: bc)
`
: basePart;
})()}
: 0
) {
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4 changes: 3 additions & 1 deletion ...m-code-helpers/string-array/templates/string-array-calls-wrapper/SelfDefendingTemplate.ts
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Expand Up @@ -57,6 +57,8 @@ export function SelfDefendingTemplate(
return ${rc4BytesIdentifier}(this.${statesIdentifier}[0]);
};

new StatesClass({stringArrayCallsWrapperName}).${checkStateIdentifier}();
if (('' + function(){return 0;}).indexOf('\\n') === -1) {
new StatesClass({stringArrayCallsWrapperName}).${checkStateIdentifier}();
}
`;
}
120 changes: 116 additions & 4 deletions ...emplates/string-array-calls-wrapper-node-template/StringArrayCallsWrapperTemplate.spec.ts
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Expand Up @@ -332,9 +332,9 @@ describe('StringArrayCallsWrapperTemplate', () => {

decodedValue = Function(`
${stringArrayTemplate}

${stringArrayCallsWrapperTemplate}

return ${stringArrayCallsWrapperName}(${index});
`)();
});
Expand Down Expand Up @@ -379,9 +379,9 @@ describe('StringArrayCallsWrapperTemplate', () => {

decodedValue = Function(`
${stringArrayTemplate}

${stringArrayCallsWrapperTemplate}

return ${stringArrayCallsWrapperName}(${index});
`)();
});
Expand All @@ -391,6 +391,118 @@ describe('StringArrayCallsWrapperTemplate', () => {
});
});
});

describe('Variant #3: correct code evaluation when engine reformats Function.prototype.toString', () => {
const origToString = Function.prototype.toString;

afterEach(() => {
Function.prototype.toString = origToString;
});

describe('Variant #1: long decoded string', () => {
const index: string = '0x0';

const indexShiftAmount: number = 0;

const expectedDecodedValue: string = 'test1test1';

let decodedValue: string;

before(() => {
const stringArrayTemplate = format(StringArrayTemplate(), {
stringArrayName,
stringArrayFunctionName,
stringArrayStorageItems: `'${cryptUtilsSwappedAlphabet.btoa('test1test1')}'`
});
const atobPolyfill = format(AtobTemplate(selfDefendingEnabled), {
atobFunctionName
});
const atobDecodeTemplate: string = format(StringArrayBase64DecodeTemplate(randomGenerator), {
atobPolyfill,
atobFunctionName,
selfDefendingCode: '',
stringArrayCacheName,
stringArrayCallsWrapperName
});
const stringArrayCallsWrapperTemplate: string = format(StringArrayCallsWrapperTemplate(), {
decodeCodeHelperTemplate: atobDecodeTemplate,
indexShiftAmount,
stringArrayCacheName,
stringArrayCallsWrapperName,
stringArrayFunctionName
});

// Simulate Bun/JSC: Function.prototype.toString adds newlines
Function.prototype.toString = function () {
return origToString.call(this).replace('){', '){\n');
};

decodedValue = Function(`
${stringArrayTemplate}

${stringArrayCallsWrapperTemplate}

return ${stringArrayCallsWrapperName}(${index});
`)();
});

it('should correctly return decoded value when engine reformats toString', () => {
assert.deepEqual(decodedValue, expectedDecodedValue);
});
});

describe('Variant #2: 3-characters decoded string', () => {
const index: string = '0x0';

const indexShiftAmount: number = 0;

const expectedDecodedValue: string = 'foo';

let decodedValue: string;

before(() => {
const stringArrayTemplate = format(StringArrayTemplate(), {
stringArrayName,
stringArrayFunctionName,
stringArrayStorageItems: `'${cryptUtilsSwappedAlphabet.btoa('foo')}'`
});
const atobPolyfill = format(AtobTemplate(selfDefendingEnabled), {
atobFunctionName
});
const atobDecodeTemplate: string = format(StringArrayBase64DecodeTemplate(randomGenerator), {
atobPolyfill,
atobFunctionName,
selfDefendingCode: '',
stringArrayCacheName,
stringArrayCallsWrapperName
});
const stringArrayCallsWrapperTemplate: string = format(StringArrayCallsWrapperTemplate(), {
decodeCodeHelperTemplate: atobDecodeTemplate,
indexShiftAmount,
stringArrayCacheName,
stringArrayCallsWrapperName,
stringArrayFunctionName
});

// Simulate Bun/JSC: Function.prototype.toString adds newlines
Function.prototype.toString = function () {
return origToString.call(this).replace('){', '){\n');
};

decodedValue = Function(`
${stringArrayTemplate}

${stringArrayCallsWrapperTemplate}

return ${stringArrayCallsWrapperName}(${index});
`)();
});

it('should correctly return decoded value when engine reformats toString', () => {
assert.deepEqual(decodedValue, expectedDecodedValue);
});
});
});
});
});

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