{"id":928,"date":"2024-05-27T11:33:54","date_gmt":"2024-05-27T03:33:54","guid":{"rendered":"https:\/\/shangwendada.top\/?p=928"},"modified":"2024-08-13T10:24:38","modified_gmt":"2024-08-13T02:24:38","slug":"ciscnandroidso_re%e9%a2%98%e8%a7%a3%e4%bb%a5%e5%8f%8a%e5%b4%a9%e6%ba%83%e5%8e%9f%e5%9b%a0%e5%88%86%e6%9e%90","status":"publish","type":"post","link":"https:\/\/blog.shangwendada.top\/index.php\/2024\/05\/27\/ciscnandroidso_re%e9%a2%98%e8%a7%a3%e4%bb%a5%e5%8f%8a%e5%b4%a9%e6%ba%83%e5%8e%9f%e5%9b%a0%e5%88%86%e6%9e%90\/","title":{"rendered":"[CISCN2024]androidso_re\u9898\u89e3\u4ee5\u53ca\u5d29\u6e83\u539f\u56e0\u5206\u6790"},"content":{"rendered":"

\u524d\u8a00<\/h2>\n

\u867d\u7136\u6ca1\u6709\u53c2\u52a0CISCN\uff0c\u4f46\u5728\u521d\u8d5b\u8d5b\u9898\u4e2d\u9047\u5230\u4e00\u4e2aAPK\u9006\u5411\u7684\u9898\u76ee\uff0c\u5bf9\u4e8e\u6700\u8fd1\u5b66\u4e60\u5b89\u5353\u6280\u80fd\u7684\u6211\u6765\u8bf4\uff0c\u6b63\u597d\u662f\u4e2a\u7ec3\u4e60\u7684\u673a\u4f1a\u3002\u5bf9\u6b64\u9898\u76ee\uff0c\u9510\u8bc4\u4e00\u4e0b\uff1a\u51fa\u9898\u4eba\u53ef\u80fd\u5728\u6d4b\u9898\u65f6\u4e0d\u591f\u4e25\u8c28\uff0c\u6216\u8005\u6545\u610f\u4e3a\u4e4b\uff0c\u5bfc\u81f4\u5f88\u591a\u4eba\u53ef\u4ee5\u76f4\u63a5hook\u5173\u952e\u70b9\uff0c\u79d2\u7834\uff0c\u4f46\u90e8\u5206\u4eba\u5374\u9891\u7e41\u9047\u5230\u5d29\u6e83\u95ee\u9898\uff0c\u5bfc\u81f4\u8fd9\u9053\u9898\u5728\u4e0d\u540c\u9009\u624b\u624b\u4e2d\u7684\u96be\u5ea6\u4e0d\u4e00\u81f4\u3002\u7136\u800c\u6b63\u597d\u6211\u5c31\u662f\u90a3\u4e2a\u9891\u7e41\u5d29\u6e83\u7684\u90a3\u4e00\u6279\uff0c\u7531\u6b64\u5206\u6790\u4e86\u4e00\u4e0b\u5d29\u6e83\u7684\u539f\u56e0\u5e76\u4e14\u5206\u4eab\u4e00\u4e0b\u89e3\u51b3\u65b9\u6cd5\u3002<\/p>\n

\u5206\u6790<\/h2>\n

\"file\"<\/div>
\n\u770b\u4e0a\u9762\u7684MainActivity\u5176\u5b9e\u53ef\u4ee5\u53d1\u73b0\u7a0b\u5e8f\u975e\u5e38\u7b80\u5355\u660e\u4e86\uff0c\u611f\u89c9\u90fd\u53ef\u4ee5\u4e00\u628a\u79d2\u3002\u4e3b\u8981\u5728legal\u91cc\u9762\uff0c\u9996\u5148\u5bf9flag\u683c\u5f0f\u505a\u4e86\u5224\u65ad\uff0c\u540e\u7eed\u624d\u5bf9flag\u5185\u5bb9\u8fdb\u884c\u5224\u65ad\uff0c\u5982\u679c\u683c\u5f0f\u4e0d\u901a\u8fc7\u5219\u4e0d\u4f1a\u89e6\u53d1jni\u7684\u5185\u5bb9\u3002<\/p>\n
paramString.length() == 38 && paramString.startsWith("flag{") && paramString.charAt(paramString.length() - 1) == '}' && !inspect.inspect(paramString.substring(5, paramString.length() - 1));<\/code><\/pre>\n
\u5982\u4e0a\u5219\u4e3a\u5224\u65ad\u8bed\u53e5\uff0c\u89c4\u5b9a\u4e86\u5f53Flag\u957f\u5ea6\u4e3a38\uff0c\u4e14\u683c\u5f0f\u6ee1\u8db3flag{xxx}\u7684\u65f6\u5019\u624d\u8fdb\u5165inspect\uff0c\u4e3b\u8981\u5224\u65ad\u903b\u8f91\u4e5f\u662f\u5728inspect\u4e2d\u5b8c\u6210\u3002<\/p>\n
\"file\"<\/div><\/p>\n
\u5ba1\u8ba1inspect\u7684\u4ee3\u7801\uff0c\u53ef\u4ee5\u53d1\u73b0\u5176\u5b9e\u5c31\u662f\u4e00\u4e2a\u666e\u901a\u7684DES\uff0c\u8fd9\u9053\u9898\u7684\u69fd\u70b9\u548c\u96be\u70b9\u5176\u5b9e\u4e5f\u5c31\u96c6\u4e2d\u5728\u8fd9\u91cc\u4e86\uff0c\u6211\u4eec\u4f1a\u53d1\u73b0\u7a0b\u5e8f\u7684Key\u548cIv\u90fd\u6765\u81ea\u4e8eNative\u5c42\uff0c\u5176\u5b9e\u5ba1\u8ba1Native\u5c42\u4ee3\u7801\u4e4b\u540e\uff0c\u5927\u5bb6\u90fd\u4f1a\u53d1\u73b0\u7b97\u6cd5\u7e41\u7410\u4e14\u590d\u6742\uff0c\u4f46\u662f\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u76f4\u63a5Hook\u7684\u65b9\u6cd5\uff0c\u53bb\u83b7\u53d6Iv\u4e0eKey\u3002
\n\u5728\u8fd9\u4e4b\u524d\uff0c\u6211\u4eec\u5f97\u5148\u770b\u770b\u8fd0\u884c\u6548\u679c\u3002
\n\u53d1\u73b0\u5982\u679c\u683c\u5f0f\u4e0d\u6ee1\u8db3\uff0c\u7a0b\u5e8f\u6b63\u5e38\u8fd4\u56deWrong<\/p>\n
\"file\"<\/div><\/p>\n
\u4e00\u65e6\u683c\u5f0f\u6ee1\u8db3\uff0c\u5219\u7a0b\u5e8f\u76f4\u63a5\u5d29\u6e83\u4e86\u3002
\n\u6211\u4eec\u901a\u8fc7LogCat\u67e5\u770b\u4e00\u4e0b\u65e5\u5fd7\uff0c\u7a76\u7adf\u8bd5\u4ec0\u4e48\u539f\u56e0\u5d29\u6e83\u3002<\/p>\n
\"file\"<\/div><\/p>\n
\u67e5\u770b\u65e5\u5fd7\uff0c\u5d29\u6e83\u539f\u56e0\u5c31\u6709\u70b9\u663e\u7136\u4e86\uff0c\u603b\u7ed3\u5982\u4e0b\uff1a<\/p>\n
\u7a0b\u5e8f\u5728\u8c03\u7528 JNI \u51fd\u6570 NewStringUTF \u65f6\u4f20\u9012\u4e86\u4e00\u4e2a\u975e\u6cd5\u7684 UTF-8 \u7f16\u7801\u5b57\u7b26\u4e32\u3002\u5177\u4f53\u6765\u8bf4\uff0c\u9519\u8bef\u65e5\u5fd7\u6307\u51fa\u8f93\u5165\u7684\u5b57\u8282\u5e8f\u5217 0x9d 0x80 0x99 0xd4 0xac 0xc9 0xd3 0xf8 \u5305\u542b\u975e\u6cd5\u7684 UTF-8 \u8d77\u59cb\u5b57\u8282 0x9d\u3002<\/p>\n
NewStringUTF \u51fd\u6570\u671f\u671b\u63a5\u6536\u4e00\u4e2a\u5408\u6cd5\u7684 UTF-8 \u7f16\u7801\u7684\u5b57\u7b26\u4e32\uff0c\u800c\u4e0d\u662f\u4efb\u610f\u5b57\u8282\u5e8f\u5217\u3002\u5982\u679c\u4f20\u5165\u7684\u5b57\u8282\u5e8f\u5217\u4e0d\u7b26\u5408 UTF-8 \u7f16\u7801\u89c4\u8303\uff0c\u5c31\u4f1a\u5bfc\u81f4 JNI \u68c0\u6d4b\u5230\u9519\u8bef\u5e76\u629b\u51fa\u5f02\u5e38\u3002<\/p>\n
\u770b\u5230\u8fd9\u91cc\u5c31\u6709\u70b9\u62bd\u8c61\u4e86\u4e3a\u5565\u4f1a\u6709\u975eUTF8\u7f16\u7801\u7684\u5b57\u7b26\u4e32\u5462\uff0c\u6211\u4eec\u53ea\u80fd\u5206\u6790\u4e00\u4e0bNative\u7684\u903b\u8f91\u4e86<\/p>\n
\u5728\u8fd9\u4e4b\u524d\u6211\u4eec\u5148\u770b\u4e00\u4e0b\u6b63\u5e38\u6765\u8bf4\u5982\u679cNative\u5c42\u9700\u8981\u8fd4\u56de\u4e00\u4e2aJstring\u5e94\u8be5\u600e\u4e48\u5199\u5462<\/p>\n
extern "C" JNIEXPORT jstring JNICALL\nJava_com_swdd_ahandroid_MainActivity_stringFromJNI(\n        JNIEnv* env,\n        jobject \/* this *\/) {\n    std::string hello = "Hello from C++";\n    return env->NewStringUTF(hello.c_str());\n}<\/code><\/pre>\n
\u6ca1\u9519\u5728return\u7684\u65f6\u5019 \u4f7f\u7528env->NewStringUTF(hello.c_str());<\/code>\u6765\u8fd4\u56deJstring\uff0c\u6240\u4ee5\u8fd9\u91cc\u51fa\u73b0\u7684\u60c5\u51b5\u5c31\u662fNewStringUTF\u629b\u51fa\u4e86\u5f02\u5e38\uff0c\u5bf9\u5e94Native\u5c42\u4ee3\u7801\u5982\u4e0b\uff1a
\n
\"file\"<\/div><\/p>\n
\u9996\u5148\u6211\u4eec\u5f97\u60f3\u529e\u6cd5\u77e5\u9053\u8fd9\u4e2a\u5bfc\u81f4\u5d29\u6e83\u7684\u516b\u4e2a\u5b57\u8282\u7a76\u7adf\u662f\u4ec0\u4e48\u4e1c\u897f
\n\u591a\u8fd0\u884c\uff0c\u591a\u5d29\u6e83\u51e0\u6b21\u53d1\u73b0\uff0c\u5982\u679c\u591a\u5c1d\u8bd5\u51e0\u6b21\u4f7f\u7528Hook\u4e3b\u52a8\u8c03\u7528GetKey\u548c\u7a0b\u5e8f\u81ea\u4e3b\u89e6\u53d1\u4ea7\u751f\u7684\u5c45\u7136\u4e0d\u4e00\u81f4\uff0c\u81f3\u6b64\u5f00\u59cb\u7384\u5b66\u8d77\u6765\u4e86\u3002
\n
\"file\"<\/div>
\n
\"file\"<\/div><\/p>\n
\u4e3a\u4e86\u65b9\u4fbf\u5206\u6790\u95ee\u9898\u6240\u5728\u7684\u5730\u65b9\uff0c\u6211\u4eec\u5199\u811a\u672cHook NewStringUTF\u770b\u770b\u548b\u4e2a\u4e8b
\nhook\u811a\u672c\u5982\u4e0b\uff1a<\/p>\n
function hookNewStringUTF() {\n    Java.perform(function () {\n        var modules = Process.enumerateModules();\n        var newStringUTFAddr = null;\n\n        for (var i = 0; i < modules.length; i++) {\n            var module = modules[i];\n            try {\n                var symbols = module.enumerateSymbols();\n                for (var j = 0; j < symbols.length; j++) {\n                    if (symbols[j].name.indexOf("NewStringUTF") >= 0) {\n                        newStringUTFAddr = symbols[j].address;\n                        console.log("Found NewStringUTF in module: " + module.name + " at: " + newStringUTFAddr + " with name: " + symbols[j].name);\n                        break;\n                    }\n                }\n            } catch (e) {\n                console.warn("Failed to enumerate symbols for module: " + module.name);\n            }\n            if (newStringUTFAddr) {\n                break;\n            }\n        }\n\n        if (newStringUTFAddr) {\n            \/\/ Hook NewStringUTF \u51fd\u6570\n            Interceptor.attach(newStringUTFAddr, {\n                onEnter: function(args) {\n                    \/\/ \u83b7\u53d6\u4f20\u5165\u7684 char* \u53c2\u6570\n                    var inputStr = args[1].readCString();\n                    console.log("NewStringUTF called with: " + inputStr);\n                },\n                onLeave: function(retval) {\n                    \/\/ \u5982\u679c\u9700\u8981\u4fee\u6539\u8fd4\u56de\u503c\uff0c\u53ef\u4ee5\u5728\u8fd9\u91cc\u8fdb\u884c\n                    console.log("NewStringUTF returning: " + retval);\n                }\n            });\n        } else {\n            console.log("NewStringUTF address not found!");\n        }\n    });\n}<\/code><\/pre>\n
\u901a\u8fc7Hook\u5f97\u5230\u7684\u503c\u5982\u4e0b\uff0c\u968f\u540e\u5c31\u5d29\u6e83\u4e86\u3002
\n
\"file\"<\/div><\/p>\n
\u7ed3\u5c3e<\/h2>\n
\u5176\u5b9e\u8fd9\u4e2a\u89e3\u51b3\u65b9\u6cd5\uff0c\u770b\u4f3c\u65e0\u89e3\uff0c\u4f46\u662f\u6211\u53d1\u73b0\u5f53\u6211\u4eec\u4f7f\u7528attach\u5bf9\u4e8egetkey\u65f6\uff0c\u7a0b\u5e8f\u5219\u6b63\u5e38\u8fd4\u56de\uff0c\u5e76\u4e14\u53d8\u5f97\u53ef\u4ee5\u8c03\u8bd5\u8fdb\u5165\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
function hook() {\n    let jni = Java.use("com.example.re11113.jni");\n    var iv = jni.getiv();\n    var getKeyBase = Module.findExportByName("libSecret_entrance.so", "Java_com_example_re11113_jni_getkey");\n\n    Interceptor.attach(getKeyBase, {\n        onEnter: function(args) {\n        },\n        onLeave: function(retval) {\n        }\n    });\n}<\/code><\/pre>\n
\u4e00\u65e6\u6211\u4eec\u9644\u52a0\u8fd9\u4e2a\u4ee3\u7801\uff0c\u539f\u672c\u4e00\u8c03\u8bd5\u5c31\u672a\u54cd\u5e94\u7684\u7a0b\u5e8f\uff0c\u53d8\u5f97\u53ef\u4ee5\u8c03\u8bd5\u4e86
\n
\"file\"<\/div>
\n\u8c03\u8bd5\u4e4b\u540e\u4e5f\u53ef\u4ee5\u770b\u5230\u6b63\u786e\u7684\u503c
\n
\"file\"<\/div>
\n\u90a3\u8fd9\u6837\uff0c\u6574\u4e2a\u7a0b\u5e8f\u5c31\u53d8\u5f97\u5fae\u5999\u4e86\u8d77\u6765\uff0c\u6d4b\u8bd5\u4e86\u5f88\u591a\u904d\uff0c\u90fd\u662f\u53ea\u6709\u5728\u4f7f\u7528\u4e0a\u8ff0\u65b9\u6cd5attach\u4e0a\u4e4b\u540e\u7a0b\u5e8f\u5c31\u4e0d\u518d\u5d29\u6e83\uff0c\u5e76\u4e14\u76ee\u524d\u6ca1\u6cd5\u627e\u5230\u539f\u56e0\u3002
\n\u65e2\u7136\u6b63\u5e38\uff0c\u8fd9\u4e2a\u9898\u7684\u9898\u7684\u9898\u89e3\u4fbf\u662f\u5982\u6b64\u4e86
\nHOOK\u4ee3\u7801\u5982\u4e0b<\/p>\n
function hook() {\n    let jni = Java.use("com.example.re11113.jni");\n    var iv = jni.getiv();\n    console.log("IV: "+iv);\n    var getKeyBase = Module.findExportByName("libSecret_entrance.so", "Java_com_example_re11113_jni_getkey");\n\n    Interceptor.attach(getKeyBase, {\n        onEnter: function(args) {\n        },\n        onLeave: function(retval) {\n        }\n    });\n    var key = jni.getKey();\n    console.log("Key: " + key);\n}<\/code><\/pre>\n
\u6700\u540e\u89e3des\u5373\u53ef
\n
\"file\"<\/div><\/p>\n","protected":false},"excerpt":{"rendered":"
\u524d\u8a00 \u867d\u7136\u6ca1\u6709\u53c2\u52a0CISCN\uff0c\u4f46\u5728\u521d\u8d5b\u8d5b\u9898\u4e2d\u9047\u5230\u4e00\u4e2aAPK\u9006\u5411\u7684\u9898\u76ee\uff0c\u5bf9\u4e8e\u6700\u8fd1\u5b66\u4e60\u5b89\u5353\u6280\u80fd\u7684\u6211\u6765\u8bf4\uff0c\u6b63\u597d\u662f\u4e2a\u7ec3 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,1],"tags":[],"class_list":["post-928","post","type-post","status-publish","format-standard","hentry","category-android","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/posts\/928","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/comments?post=928"}],"version-history":[{"count":14,"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/posts\/928\/revisions"}],"predecessor-version":[{"id":954,"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/posts\/928\/revisions\/954"}],"wp:attachment":[{"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/media?parent=928"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/categories?post=928"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.shangwendada.top\/index.php\/wp-json\/wp\/v2\/tags?post=928"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}