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[原创]利用frida和dexlib2进行字符串反混淆
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发表于: 2025-12-3 17:28
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都是传入了一个函数来解密的格式
思路：用frida去hook最后的结果，然后用dexlib2来patch
目前写了一个小demo,尝试对一个地方进行patch
踩雷：
修改成
应该是长度对不齐，就会失败，对齐之后会发现确实去掉了这个地方
利用frida打一个表，然后尝试批量化
凡是在frida里面被hook调用到的都会被patch回去
最后改成遍历所有类就ok了，重写了回溯，成功
最终版本
package org.example;import com.google.common.collect.Lists;import org.jf.dexlib2.DexFileFactory;import org.jf.dexlib2.Opcodes;import org.jf.dexlib2.iface.ClassDef;import org.jf.dexlib2.iface.DexFile;import org.jf.dexlib2.iface.Method;import org.jf.dexlib2.iface.MethodImplementation;import org.jf.dexlib2.iface.instruction.Instruction;import org.jf.dexlib2.iface.instruction.OneRegisterInstruction;import org.jf.dexlib2.iface.instruction.ReferenceInstruction;import org.jf.dexlib2.iface.reference.StringReference;import org.jf.dexlib2.builder.MutableMethodImplementation;import org.jf.dexlib2.builder.instruction.BuilderInstruction21c;import org.jf.dexlib2.immutable.reference.ImmutableStringReference;import org.jf.dexlib2.builder.instruction.BuilderInstruction10x;import org.jf.dexlib2.Opcode;import org.jf.dexlib2.immutable.ImmutableClassDef;import org.jf.dexlib2.immutable.ImmutableMethod;import org.jf.dexlib2.writer.io.FileDataStore;import org.jf.dexlib2.writer.pool.DexPool;import org.jf.dexlib2.builder.BuilderInstruction;import org.jf.dexlib2.immutable.ImmutableMethodImplementation;import java.io.File;import java.io.IOException;import java.util.ArrayList;import java.util.List;public class Main { public static void main(String[] args) throws IOException { File file = new File("C:\\Users\\cpq\\IdeaProjects\\untitled\\src\\main\\resources\\classes03.dex"); DexFile dexFile = DexFileFactory.loadDexFile(file, Opcodes.getDefault()); // 1. 创建 DexPool 用于重组和写入 Dex DexPool dexPool = new DexPool(Opcodes.getDefault()); for (ClassDef classDef : dexFile.getClasses()) { if (classDef.getType().equals("Lio/liankong/riskdetector/core/VO0O0OOOOOOO0;")) { System.out.println("Processing target class: " + classDef.getType()); // 2. 获取修改后的类定义 ClassDef modifiedClass = ReplaceStr(classDef); dexPool.internClass(modifiedClass); } else { // 3. 非目标类直接原样放入池中 dexPool.internClass(classDef); } } // 4. 保存文件 File outFile = new File("classes03_patched.dex"); System.out.println("Writing to " + outFile.getAbsolutePath()); dexPool.writeTo(new FileDataStore(outFile)); System.out.println("Done."); } private static ClassDef ReplaceStr(ClassDef classDef) { boolean isClassModified = false; List<Method> newMethods = new ArrayList<>(); for (Method method : classDef.getMethods()) { MethodImplementation methodImpl = method.getImplementation(); // 仅处理 <clinit> 且有实现的方法 if (methodImpl != null && method.getName().equals("<clinit>")) { MutableMethodImplementation mutableImpl = new MutableMethodImplementation(methodImpl); // === Fix 1: 必须复制到一个新的 ArrayList 中 === // mutableImpl.getInstructions() 返回的是只读视图，不能直接 set List<BuilderInstruction> instructions = new ArrayList<>(mutableImpl.getInstructions()); boolean isMethodModified = false; for (int i = 0; i < instructions.size(); i++) { Instruction instruction = instructions.get(i); if (instruction instanceof ReferenceInstruction) { ReferenceInstruction refInst = (ReferenceInstruction) instruction; if (refInst.getReference() instanceof org.jf.dexlib2.iface.reference.MethodReference) { org.jf.dexlib2.iface.reference.MethodReference methodRef = (org.jf.dexlib2.iface.reference.MethodReference) refInst .getReference(); if (methodRef.getDefiningClass().equals("Lio/liankong/riskdetector/OO0O0000O000;") && methodRef.getName().equals("IIIIIIIILIII")) { System.out.println("Found target call at index " + i); if (i >= 2) { Instruction prev1 = instructions.get(i - 1); Instruction prev2 = instructions.get(i - 2); if (prev1.getOpcode().name.startsWith("const-string") && prev2.getOpcode().name.startsWith("const-string")) { String str1 = ((StringReference) ((ReferenceInstruction) prev1).getReference()) .getString(); String str2 = ((StringReference) ((ReferenceInstruction) prev2).getReference()) .getString(); if (str2.contains("ggFH+206pVWHeByNO0rnJtdlR40APuch1xYmkHAu3TnsX1DGAGyuaYM=") && str1.contains("qj59oF0XnBQ=")) { System.out.println(" --> Patching..."); int targetReg = ((OneRegisterInstruction) prev2).getRegisterA(); BuilderInstruction newConstStr = new BuilderInstruction21c( Opcode.CONST_STRING, targetReg, new ImmutableStringReference("\u98ce\u9669App\u68c0\u6d4b")); BuilderInstruction nop = new BuilderInstruction10x(Opcode.NOP); instructions.set(i, newConstStr); instructions.set(i+1,newConstStr); // if (i + 1 < instructions.size()) { // instructions.set(i + 1, nop); // } isMethodModified = true; isClassModified = true; } } } } } } } if (isMethodModified) { // === Fix 2: 使用修改后的指令列表构建新的 Implementation === // 我们不能复用 mutableImpl，因为它里面的列表没变。我们手动创建一个 ImmutableImplementation。 MethodImplementation newImplementation = new ImmutableMethodImplementation( mutableImpl.getRegisterCount(), instructions, // 我们修改后的 List mutableImpl.getTryBlocks(), mutableImpl.getDebugItems()); newMethods.add(new ImmutableMethod( method.getDefiningClass(), method.getName(), method.getParameters(), method.getReturnType(), method.getAccessFlags(), method.getAnnotations(), method.getHiddenApiRestrictions(), newImplementation // 传入新的实现 )); } else { newMethods.add(method); // 未修改，保留原样 } } else { newMethods.add(method); // 其他方法，保留原样 } } if (isClassModified) { return new ImmutableClassDef( classDef.getType(), classDef.getAccessFlags(), classDef.getSuperclass(), classDef.getInterfaces(), classDef.getSourceFile(), classDef.getAnnotations(), classDef.getFields(), newMethods); } else { return classDef; } }}package org.example;import com.google.common.collect.Lists;import org.jf.dexlib2.DexFileFactory;import org.jf.dexlib2.Opcodes;import org.jf.dexlib2.iface.ClassDef;import org.jf.dexlib2.iface.DexFile;import org.jf.dexlib2.iface.Method;import org.jf.dexlib2.iface.MethodImplementation;import org.jf.dexlib2.iface.instruction.Instruction;import org.jf.dexlib2.iface.instruction.OneRegisterInstruction;import org.jf.dexlib2.iface.instruction.ReferenceInstruction;import org.jf.dexlib2.iface.reference.StringReference;import org.jf.dexlib2.builder.MutableMethodImplementation;import org.jf.dexlib2.builder.instruction.BuilderInstruction21c;import org.jf.dexlib2.immutable.reference.ImmutableStringReference;import org.jf.dexlib2.builder.instruction.BuilderInstruction10x;import org.jf.dexlib2.Opcode;import org.jf.dexlib2.immutable.ImmutableClassDef;import org.jf.dexlib2.immutable.ImmutableMethod;import org.jf.dexlib2.writer.io.FileDataStore;import org.jf.dexlib2.writer.pool.DexPool;import org.jf.dexlib2.builder.BuilderInstruction;import org.jf.dexlib2.immutable.ImmutableMethodImplementation;import java.io.File;import java.io.IOException;import java.util.ArrayList;import java.util.List;public class Main { public static void main(String[] args) throws IOException { File file = new File("C:\\Users\\cpq\\IdeaProjects\\untitled\\src\\main\\resources\\classes03.dex"); DexFile dexFile = DexFileFactory.loadDexFile(file, Opcodes.getDefault()); // 1. 创建 DexPool 用于重组和写入 Dex DexPool dexPool = new DexPool(Opcodes.getDefault()); for (ClassDef classDef : dexFile.getClasses()) { if (classDef.getType().equals("Lio/liankong/riskdetector/core/VO0O0OOOOOOO0;")) { System.out.println("Processing target class: " + classDef.getType()); // 2. 获取修改后的类定义 ClassDef modifiedClass = ReplaceStr(classDef); dexPool.internClass(modifiedClass); } else { // 3. 非目标类直接原样放入池中 dexPool.internClass(classDef); } } // 4. 保存文件 File outFile = new File("classes03_patched.dex"); System.out.println("Writing to " + outFile.getAbsolutePath()); dexPool.writeTo(new FileDataStore(outFile)); System.out.println("Done."); } private static ClassDef ReplaceStr(ClassDef classDef) { boolean isClassModified = false; List<Method> newMethods = new ArrayList<>(); for (Method method : classDef.getMethods()) { MethodImplementation methodImpl = method.getImplementation(); // 仅处理 <clinit> 且有实现的方法 if (methodImpl != null && method.getName().equals("<clinit>")) { MutableMethodImplementation mutableImpl = new MutableMethodImplementation(methodImpl); // === Fix 1: 必须复制到一个新的 ArrayList 中 === // mutableImpl.getInstructions() 返回的是只读视图，不能直接 set List<BuilderInstruction> instructions = new ArrayList<>(mutableImpl.getInstructions()); boolean isMethodModified = false; for (int i = 0; i < instructions.size(); i++) { Instruction instruction = instructions.get(i); if (instruction instanceof ReferenceInstruction) { ReferenceInstruction refInst = (ReferenceInstruction) instruction; if (refInst.getReference() instanceof org.jf.dexlib2.iface.reference.MethodReference) { org.jf.dexlib2.iface.reference.MethodReference methodRef = (org.jf.dexlib2.iface.reference.MethodReference) refInst .getReference(); if (methodRef.getDefiningClass().equals("Lio/liankong/riskdetector/OO0O0000O000;") && methodRef.getName().equals("IIIIIIIILIII")) { System.out.println("Found target call at index " + i); if (i >= 2) { Instruction prev1 = instructions.get(i - 1); Instruction prev2 = instructions.get(i - 2); if (prev1.getOpcode().name.startsWith("const-string") && prev2.getOpcode().name.startsWith("const-string")) { String str1 = ((StringReference) ((ReferenceInstruction) prev1).getReference()) .getString(); String str2 = ((StringReference) ((ReferenceInstruction) prev2).getReference()) .getString(); if (str2.contains("ggFH+206pVWHeByNO0rnJtdlR40APuch1xYmkHAu3TnsX1DGAGyuaYM=") && str1.contains("qj59oF0XnBQ=")) { System.out.println(" --> Patching..."); int targetReg = ((OneRegisterInstruction) prev2).getRegisterA(); BuilderInstruction newConstStr = new BuilderInstruction21c( Opcode.CONST_STRING, targetReg, new ImmutableStringReference("\u98ce\u9669App\u68c0\u6d4b")); BuilderInstruction nop = new BuilderInstruction10x(Opcode.NOP); instructions.set(i, newConstStr); instructions.set(i+1,newConstStr); // if (i + 1 < instructions.size()) { // instructions.set(i + 1, nop); // } isMethodModified = true; isClassModified = true; } } } } } } } if (isMethodModified) { // === Fix 2: 使用修改后的指令列表构建新的 Implementation === // 我们不能复用 mutableImpl，因为它里面的列表没变。我们手动创建一个 ImmutableImplementation。 MethodImplementation newImplementation = new ImmutableMethodImplementation( mutableImpl.getRegisterCount(), instructions, // 我们修改后的 List mutableImpl.getTryBlocks(), mutableImpl.getDebugItems()); newMethods.add(new ImmutableMethod( method.getDefiningClass(), method.getName(), method.getParameters(), method.getReturnType(), method.getAccessFlags(), method.getAnnotations(), method.getHiddenApiRestrictions(), newImplementation // 传入新的实现 )); } else { newMethods.add(method); // 未修改，保留原样 } } else { newMethods.add(method); // 其他方法，保留原样 } } if (isClassModified) { return new ImmutableClassDef( classDef.getType(), classDef.getAccessFlags(), classDef.getSuperclass(), classDef.getInterfaces(), classDef.getSourceFile(), classDef.getAnnotations(), classDef.getFields(), newMethods); } else { return classDef; } }}Java.perform(function () { var OO0O0000O000 = Java.use("io.liankong.riskdetector.OO0O0000O000");OO0O0000O000["IIIIIIIILIII"].implementation = function (str, str2) { let result = this["IIIIIIIILIII"](str, str2); str = str.replace(/\n/g, ''); str2 = str2.replace(/\n/g, ''); console.log(`${str2},${str}:${result}`); return result;}; });Java.perform(function () { var OO0O0000O000 = Java.use("io.liankong.riskdetector.OO0O0000O000");OO0O0000O000["IIIIIIIILIII"].implementation = function (str, str2) { let result = this["IIIIIIIILIII"](str, str2); str = str.replace(/\n/g, ''); str2 = str2.replace(/\n/g, ''); console.log(`${str2},${str}:${result}`); return result;}; });package org.example;import org.jf.dexlib2.DexFileFactory;import org.jf.dexlib2.Opcodes;import org.jf.dexlib2.Opcode;import org.jf.dexlib2.iface.ClassDef;import org.jf.dexlib2.iface.DexFile;import org.jf.dexlib2.iface.Method;import org.jf.dexlib2.iface.MethodImplementation;import org.jf.dexlib2.iface.instruction.Instruction;import org.jf.dexlib2.iface.instruction.OneRegisterInstruction;import org.jf.dexlib2.iface.instruction.ReferenceInstruction;import org.jf.dexlib2.iface.reference.StringReference;import org.jf.dexlib2.builder.MutableMethodImplementation;import org.jf.dexlib2.builder.instruction.BuilderInstruction21c;import org.jf.dexlib2.builder.instruction.BuilderInstruction10x;import org.jf.dexlib2.immutable.reference.ImmutableStringReference;import org.jf.dexlib2.immutable.ImmutableClassDef;import org.jf.dexlib2.immutable.ImmutableMethod;import org.jf.dexlib2.immutable.ImmutableMethodImplementation;import org.jf.dexlib2.writer.io.FileDataStore;import org.jf.dexlib2.writer.pool.DexPool;import org.jf.dexlib2.builder.BuilderInstruction;import java.io.File;import java.io.IOException;import java.nio.charset.StandardCharsets;import java.nio.file.Files;import java.nio.file.Paths;import java.util.ArrayList;import java.util.List;public class Main { static class PatchConfig { String targetStr1; // 对应参数 v2 (例如 key) String targetStr2; // 对应参数 v0 (例如密文) String newStr; // 替换后的明文 public PatchConfig(String t1, String t2, String n) { this.targetStr1 = t1; this.targetStr2 = t2; this.newStr = n; } } public static void main(String[] args) throws IOException { // 输入和输出文件路径 File file = new File("C:\\Users\\cpq\\IdeaProjects\\untitled\\src\\main\\resources\\classes03.dex"); String configPath = "C:\\Users\\cpq\\IdeaProjects\\untitled\\src\\main\\resources\\tmp.txt"; // 配置文件路径 File outFile = new File("classes03_patched.dex"); List<PatchConfig> patchConfigs = new ArrayList<>(); List<String> lines = Files.readAllLines(Paths.get(configPath), StandardCharsets.UTF_8); for (String line : lines) { if (line.trim().isEmpty() || line.startsWith("#")) continue; String[] parts = line.split(":", 2); if (parts.length == 2) { String encryptedPart = parts[0]; String newStr = parts[1]; String[] encParams = encryptedPart.split(","); if (encParams.length >= 2) { String t1 = encParams[0].trim(); String t2 = encParams[1].trim(); // 将解析结果存入列表 去重 if (patchConfigs.stream().noneMatch(pc -> pc.targetStr1.equals(t1) && pc.targetStr2.equals(t2))) { patchConfigs.add(new PatchConfig(t1, t2, newStr)); } } else { System.err.println("Skipping invalid line (comma missing): " + line); } } else { System.err.println("Skipping invalid line (colon missing): " + line); } } System.out.println("Loaded " + patchConfigs.size() + " replacement rules."); // 2. 加载 Dex DexFile dexFile = DexFileFactory.loadDexFile(file, Opcodes.getDefault()); DexPool dexPool = new DexPool(Opcodes.getDefault()); // 3. 遍历并修改类 for (ClassDef classDef : dexFile.getClasses()) { if (classDef.getType().contains("io/liankong/riskdetector")) { System.out.println("Processing target class: " + classDef.getType()); ClassDef currentClass = classDef; for (PatchConfig config : patchConfigs) { currentClass = ReplaceStr( currentClass, "Lio/liankong/riskdetector/OO0O0000O000;", // 解密函数所在类 "IIIIIIIILIII", // 解密函数名 config.targetStr1, // 对应 mapping 中的 TargetStr1 config.targetStr2, // 对应 mapping 中的 TargetStr2 config.newStr // 对应 mapping 中的 NewStr ); } dexPool.internClass(currentClass); } else { dexPool.internClass(classDef); } } // 4. 保存文件 System.out.println("Writing to " + outFile.getAbsolutePath()); dexPool.writeTo(new FileDataStore(outFile)); System.out.println("Done."); } private static ClassDef ReplaceStr(ClassDef classDef, String ClassName, String MethodName, String TargetStr1, String TargetStr2, String NewStr) { boolean isClassModified = false; List<Method> newMethods = new ArrayList<>(); for (Method method : classDef.getMethods()) { MethodImplementation methodImpl = method.getImplementation(); if (methodImpl != null) { MutableMethodImplementation mutableImpl = new MutableMethodImplementation(methodImpl); List<BuilderInstruction> instructions = new ArrayList<>(mutableImpl.getInstructions()); boolean isMethodModified = false; for (int i = 0; i < instructions.size(); i++) { Instruction instruction = instructions.get(i); if (instruction instanceof ReferenceInstruction) { ReferenceInstruction refInst = (ReferenceInstruction) instruction; if (refInst.getReference() instanceof org.jf.dexlib2.iface.reference.MethodReference) { org.jf.dexlib2.iface.reference.MethodReference methodRef = (org.jf.dexlib2.iface.reference.MethodReference) refInst .getReference(); if (methodRef.getDefiningClass().equals(ClassName) && methodRef.getName().equals(MethodName)) { String foundContent = null; // 离 invoke 最近的 (参数2) String foundKey = null; // 离 invoke 较远的 (参数1) int foundCount = 0; // 向上回溯查找前两个 const-string for (int k = i - 1; k >= 0; k--) { Instruction prev = instructions.get(k); if (prev.getOpcode().name.startsWith("const-string")) { String val = ((StringReference) ((ReferenceInstruction) prev).getReference()).getString(); if (foundCount == 0) { foundContent = val; foundCount++; } else if (foundCount == 1) { foundKey = val; foundCount++; break; } } // 防止回溯过远 (可选) if (i - k > 30) break; } // 检查是否匹配 if (foundCount == 2 && foundKey.contains(TargetStr2) && foundContent.contains(TargetStr1)) { System.out.println("Patching found in: " + method.getName()); int targetReg = 0; boolean hasMoveResult = false; if (i + 1 < instructions.size()) { Instruction nextInst = instructions.get(i + 1); if (nextInst.getOpcode().name.startsWith("move-result")) { targetReg = ((OneRegisterInstruction) nextInst).getRegisterA(); hasMoveResult = true; } } if (hasMoveResult) { BuilderInstruction newConstStr = new BuilderInstruction21c( Opcode.CONST_STRING, targetReg, new ImmutableStringReference(NewStr)); BuilderInstruction nop = new BuilderInstruction10x(Opcode.NOP); // 替换 invoke instructions.set(i, newConstStr); instructions.set(i + 1, newConstStr); isMethodModified = true; isClassModified = true; } else { System.err.println("Warning: No move-result after invoke, skipping patch."); } } } } } } if (isMethodModified) { MethodImplementation newImplementation = new ImmutableMethodImplementation( mutableImpl.getRegisterCount(), instructions, // 我们修改后的 List mutableImpl.getTryBlocks(), mutableImpl.getDebugItems()); newMethods.add(new ImmutableMethod( method.getDefiningClass(), method.getName(), method.getParameters(), method.getReturnType(), method.getAccessFlags(), method.getAnnotations(), method.getHiddenApiRestrictions(), newImplementation // 传入新的实现 )); } else { newMethods.add(method); // 未修改，保留原样 } } else { newMethods.add(method); // 其他方法，保留原样 } } if (isClassModified) { return new ImmutableClassDef( classDef.getType(), classDef.getAccessFlags(), classDef.getSuperclass(), classDef.getInterfaces(), classDef.getSourceFile(), classDef.getAnnotations(), classDef.getFields(), newMethods); } else { return classDef; } }}package org.example;import org.jf.dexlib2.DexFileFactory;import org.jf.dexlib2.Opcodes;import org.jf.dexlib2.Opcode;import org.jf.dexlib2.iface.ClassDef;import org.jf.dexlib2.iface.DexFile;import org.jf.dexlib2.iface.Method;import org.jf.dexlib2.iface.MethodImplementation;import org.jf.dexlib2.iface.instruction.Instruction;import org.jf.dexlib2.iface.instruction.OneRegisterInstruction;import org.jf.dexlib2.iface.instruction.ReferenceInstruction;
最后于 2025-12-3 17:34
被BediveRe_编辑
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