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本帖最后由 luozhenni 于 2022-4-15 13:51 编辑
某安全网关前端JS分析
Ainrm 衡阳信安 2022-04-15 05:06
原文链接：某安全网关前端JS分析
前言
xxx是一款用于前端防御自动化工具的安全网关，核心代码由服务器下发给客户端执行，通过cookie将执行结果带回，再根据js获取的前端数据判断用户是否异常，完成安全检测
一、代码入口
js计算结果通过cookie传给服务器，参数名为：8PHkpr8y、JF7cGtR5、SflKxwRJ
 
经过调试分析，代码明文存放在ng_dynamic_defend文件中，核心逻辑位于尾部这几行
二、读取配置
get_global（）函数读取配置信息，放入_global_config中
- window.config = 'eyJmaW5nZXIiOnsibmFtZSI6IkpGN2NHdFI1In0sImJvdCI6eyJlbmFibGVkIjp0cnVlLCJuYW1lIjoiOFBIa3ByOHkifSwic3VibWl0Ijp7ImVuYWJsZWQiOnRydWUsIm5hbWUiOiJVVmpES082biIsInVybCI6IiJ9LCJ0b2tlbiI6eyJlbmFibGVkIjp0cnVlLCJuYW1lIjoiU2ZsS3h3UkoiLCJ1cmwiOiJqc190ZXN0LmNvbTsiLCJpc19jaGVja191cmkiOnRydWUsImlzX2NoZWNrX2dldCI6dHJ1ZX0sImNvbnRlbnQiOnsiZW5hYmxlZCI6ZmFsc2UsIm5hbWUiOiJTZmxLeHdSSiIsImNvbmZ1c2VfdHlwZSI6IjAifSwic2NyaXB0Ijp7ImlzX2FudGlfZGVidWciOmZhbHNlfX0=';
- !function (global) {
- function _base64_parse(e) {
- return CryptoJS.enc.Base64.parse(e).toString(CryptoJS.enc.Utf8) }
- function get_global() {
- var e = _base64_parse(global.config), t = JSON.parse(e);
- _global_config = global.nY1vq7Gi = t }
- }
- (window);
- /*{
- "finger": { "name": "JF7cGtR5" },
- "bot": { "enabled": true, "name": "8PHkpr8y" },
- "submit": { "enabled": true, "name": "UVjDKO6n", "url": "" },
- "token": { "enabled": true, "name": "SflKxwRJ", "url": "js_test.com;", "is_check_uri": true, "is_check_get": true },
- "content": { "enabled": false, "name": "SflKxwRJ", "confuse_type": "0" },
- "script": { "is_anti_debug": false }}
- */
以下三个函数会使用到window对象来采集客户端数据：
- get_tool_feature() 获得工具特征
- get_browser_feature() 获得浏览器特征
- get_fingerprint() 获得浏览器指纹
3.1 get_tool_feature()
- get_webdriver() //window.navigator.webdriver
- get_phantomjs() //window.navigator.userAgent
- get_bot() //检测关键字：'__webdriver_evaluate','__selenium_evaluate','__webdriver_script_function','__webdriver_script_func','__webdriver_script_fn','__fxdriver_evaluate','__driver_unwrapped','__webdriver_unwrapped','__driver_evaluate','__selenium_unwrapped','__fxdriver_unwrapped''_phantom','__nightmare','_selenium','callPhantom','callSelenium','_Selenium_IDE_Recorder'get_navigator_for_tool() //window.navigator.languagesget_canvas_for_tool() //window.document.createElement('canvas').getContextget_storage_for_tool() //window.localStorage && window.sessionStorageget_consol() //window.console.log(1)
- get_awvs() //检测关键字：'SimpleDOMXSSClass','MarvinHooks','MarvinPageExplorer','HashDOMXSSClass'
- get_appscan() //检测关键字：'appScanSendReplacement','appScanOnReadyStateChangeReplacement','appScanLoadHandler','appScanSetPageLoaded'
3.2 get_browser_feature()- get_indexedDB() //window.indexedDBget_openDatabase() //window.openDatabaseget_localStorage() //window.localStorageget_sessionStorage() //window.sessionStorageget_audio() //window.AudioContext.destinationget_file() //'object' == typeof File || 'function' == typeof FileisCanvasSupported() //window.document.createElement('canvas').getContextisWebGlSupported() //window.WebGLRenderingContext || window.document.createElement('canvas').getContext('webgl')get_plugins() //window.navigator.pluginsget_languages() //window.navigator.languagesget_platform() //window.navigator.platformget_cpuClass() //_navigator.cpuClassget_hardwareConcurrency() //_navigator.hardwareConcurrencyget_namespaces() //window.document.namespacesget_documentMode() //window.document.documentModeget_ActivexObject() //window.document.ActivexObjectget_StyleMedia() //window.StyleMediaget_opera() //window.operaget_firefox() //'undefined' != typeof InstallTriggerget_chrome() //window.chromeget_safari() ///constructor/i.test(window.HTMLElement) || '[object SafariRemoteNotification]' === (!window.safari || safari.pushNotification).toString()
3.3 get_fingerprint()- get_indexedDB() //window.indexedDBget_openDatabase() //window.openDatabaseget_localStorage() //window.localStorage
- get_sessionStorage() //window.sessionStorage
- get_audio() //window.AudioContext.destinationget_file() //'object' == typeof File || 'function' == typeof File
- get_canvas() //window.document.createElement('canvas')
- get_webgl() //window..document.createElement('canvas').getContext('webgl')get_webgl_render() //window.document.createElement('canvas').getContext('webgl')
- get_plugins() //window.navigator.pluginsget_language() //window.navigator.language || window.navigator.userLanguage || window.navigator.browserLanguage || window.navigator.systemLanguage ||get_languages() //window.navigator.languagesget_platform() //window.navigator.platformget_cpuClass() //window.navigator.cpuClassget_hardwareConcurrency() //window.navigator.hardwareConcurrency
- get_timezone_offset() //(new Date).getTimezoneOffset()get_timezone() //window.Intl && window.Intl.DateTimeFormatget_screen_ratio() //window.screen.width / window.screen.height * 100get_screen_resolution() //window.screen.availHeight + 'X' + window.screen.availWidth + 'X' + window.screen.availLeft + 'X' + window.screen.availTopget_touch_support() //window.navigator.maxTouchPoints || window.navigator.msMaxTouchPointsget_media_devices() //window.navigator.mediaDevices && window.navigator.mediaDevices.enumerateDevicesget_battery() //window.navigator.getBatteryget_adBlock() //window.document.getElementsByClassName('adsbox') [0].offsetHeightget_userAgent() //window.navigator.userAgent
3.4 数据处理
set_bot_cookie()、set_fingerprint()两个函数分别将tool_feature、browser_feature与fingerprint加密写入到cokie中，变量名为：8PHkpr8y、JF7cGtR5
set_fingerprint()
四、 事件监听
4.1 a标签
设置EventListenerEx()监听，当页面加载完成时触发load_func()，对当前cookie执行base64编码操作，并设置参数名为KBwtGA
function confuse_cookie() { var e; _document.cookie && 0 != _global_config.content.enabled && '1' == _global_config.content.confuse_type && (e = _document.cookie, clearAllCookie(), CookieUtil.set('KBwtGA', btoa(e)))}
当发生点击事件时触发a_click_handler()，对请求地址添加令牌，变量名为SflKxwRJ
replace_url()调用get_token()生成加密tonken
4.2 form表单
设置EventListenerEx()监听，当发生表单事件时触发form_hook()，调用get_submit()对表单内数据加密，参数名为UVjDKO6n，调用get_token()生成加密tonken，参数名为SflKxwRJ
4.3 ajax请求
当发生ajax事件时触发ajax_hook()，对不同请求方式做了单独处理
xxx的核心代码未经过加密或混淆以明文形式下发，格式化后通过调试分析比较容易弄清楚执行逻辑，代码主要实现以下两个功能：
- 采集window或者navigator的部分特征值，按位计算形成一个整数，再利用rc4算法加密，指纹特征存放在cookie中JF7cGtR5、工具特征存放在cookie中8PHkpr8y
- 设置a标签、form表单、ajax请求监听，触发时对数据内容调用get_submit()使用rc4算法加密、对url调用get_token()使用rc4算法计算token令牌
来源：先知(https://xz.aliyun.com/t/11189)
注：如有侵权请联系删除
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发表于 2022-4-15 13:51:20