CNVDSpider

Crawl CNVD shared vulnerabilities with js

完整教程查看博客

写论文需要用到CNVD漏洞库的数据，然而，该页面有反爬机制，无法抓取全部数据，因此，使用js绕过反爬，实现效果如下：

可以直接到GitHub查看完整代码，欢迎留言点赞打赏提issue点star

环境

windows 10
Chrome浏览器
Sublime Text 3代码编辑器

前期准备

注册该网页账号并登陆即可

需求分析

首先，我们需要该漏洞库的全部漏洞数据，但是，使用python书写爬虫会被反爬机制识别到，从而无法自动大量下载数据
这里，发现该网页有共享的xml数据因此，我们考虑从这里做文章
然鹅，一个个点击下载也十分耗时，因此，考虑使用js脚本进行下载
这里有两个思路：

一是分别控制脚本挨个点击链接并翻页
二是直接请求每个链接获得数据

这里采用第二种思路，通过查看链接发现其均为https://www.cnvd.org.cn/shareData/download/ + 一个数字的形式，因此，直接使用循环遍历请求即可

代码编写

确定了思路之后，直接开始编写代码，但是遇到了一个问题，就是浏览器无法通过js请求直接保存为本地文件，这里借鉴了一篇博客，使用FileSaver.js这个脚本来实现js下载文件到本地

FileSaver.js

该脚本代码如下：

/* FileSaver.js
 * A saveAs() FileSaver implementation.
 * 1.3.2
 * 2016-06-16 18:25:19
 *
 * By Eli Grey, http://eligrey.com
 * License: MIT
 *   See https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md
 */
 
/*global self */
/*jslint bitwise: true, indent: 4, laxbreak: true, laxcomma: true, smarttabs: true, plusplus: true */
 
/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js */
 
var saveAs = saveAs || (function(view) {
    "use strict";
    // IE <10 is explicitly unsupported
    if (typeof view === "undefined" || typeof navigator !== "undefined" && /MSIE [1-9]\./.test(navigator.userAgent)) {
        return;
    }
    var
          doc = view.document
          // only get URL when necessary in case Blob.js hasn't overridden it yet
        , get_URL = function() {
            return view.URL || view.webkitURL || view;
        }
        , save_link = doc.createElementNS("http://www.w3.org/1999/xhtml", "a")
        , can_use_save_link = "download" in save_link
        , click = function(node) {
            var event = new MouseEvent("click");
            node.dispatchEvent(event);
        }
        , is_safari = /constructor/i.test(view.HTMLElement) || view.safari
        , is_chrome_ios =/CriOS\/[\d]+/.test(navigator.userAgent)
        , throw_outside = function(ex) {
            (view.setImmediate || view.setTimeout)(function() {
                throw ex;
            }, 0);
        }
        , force_saveable_type = "application/octet-stream"
        // the Blob API is fundamentally broken as there is no "downloadfinished" event to subscribe to
        , arbitrary_revoke_timeout = 1000 * 40 // in ms
        , revoke = function(file) {
            var revoker = function() {
                if (typeof file === "string") { // file is an object URL
                    get_URL().revokeObjectURL(file);
                } else { // file is a File
                    file.remove();
                }
            };
            setTimeout(revoker, arbitrary_revoke_timeout);
        }
        , dispatch = function(filesaver, event_types, event) {
            event_types = [].concat(event_types);
            var i = event_types.length;
            while (i--) {
                var listener = filesaver["on" + event_types[i]];
                if (typeof listener === "function") {
                    try {
                        listener.call(filesaver, event || filesaver);
                    } catch (ex) {
                        throw_outside(ex);
                    }
                }
            }
        }
        , auto_bom = function(blob) {
            // prepend BOM for UTF-8 XML and text/* types (including HTML)
            // note: your browser will automatically convert UTF-16 U+FEFF to EF BB BF
            if (/^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {
                return new Blob([String.fromCharCode(0xFEFF), blob], {type: blob.type});
            }
            return blob;
        }
        , FileSaver = function(blob, name, no_auto_bom) {
            if (!no_auto_bom) {
                blob = auto_bom(blob);
            }
            // First try a.download, then web filesystem, then object URLs
            var
                  filesaver = this
                , type = blob.type
                , force = type === force_saveable_type
                , object_url
                , dispatch_all = function() {
                    dispatch(filesaver, "writestart progress write writeend".split(" "));
                }
                // on any filesys errors revert to saving with object URLs
                , fs_error = function() {
                    if ((is_chrome_ios || (force && is_safari)) && view.FileReader) {
                        // Safari doesn't allow downloading of blob urls
                        var reader = new FileReader();
                        reader.onloadend = function() {
                            var url = is_chrome_ios ? reader.result : reader.result.replace(/^data:[^;]*;/, 'data:attachment/file;');
                            var popup = view.open(url, '_blank');
                            if(!popup) view.location.href = url;
                            url=undefined; // release reference before dispatching
                            filesaver.readyState = filesaver.DONE;
                            dispatch_all();
                        };
                        reader.readAsDataURL(blob);
                        filesaver.readyState = filesaver.INIT;
                        return;
                    }
                    // don't create more object URLs than needed
                    if (!object_url) {
                        object_url = get_URL().createObjectURL(blob);
                    }
                    if (force) {
                        view.location.href = object_url;
                    } else {
                        var opened = view.open(object_url, "_blank");
                        if (!opened) {
                            // Apple does not allow window.open, see https://developer.apple.com/library/safari/documentation/Tools/Conceptual/SafariExtensionGuide/WorkingwithWindowsandTabs/WorkingwithWindowsandTabs.html
                            view.location.href = object_url;
                        }
                    }
                    filesaver.readyState = filesaver.DONE;
                    dispatch_all();
                    revoke(object_url);
                }
            ;
            filesaver.readyState = filesaver.INIT;
 
            if (can_use_save_link) {
                object_url = get_URL().createObjectURL(blob);
                setTimeout(function() {
                    save_link.href = object_url;
                    save_link.download = name;
                    click(save_link);
                    dispatch_all();
                    revoke(object_url);
                    filesaver.readyState = filesaver.DONE;
                });
                return;
            }
 
            fs_error();
        }
        , FS_proto = FileSaver.prototype
        , saveAs = function(blob, name, no_auto_bom) {
            return new FileSaver(blob, name || blob.name || "download", no_auto_bom);
        }
    ;
    // IE 10+ (native saveAs)
    if (typeof navigator !== "undefined" && navigator.msSaveOrOpenBlob) {
        return function(blob, name, no_auto_bom) {
            name = name || blob.name || "download";
 
            if (!no_auto_bom) {
                blob = auto_bom(blob);
            }
            return navigator.msSaveOrOpenBlob(blob, name);
        };
    }
 
    FS_proto.abort = function(){};
    FS_proto.readyState = FS_proto.INIT = 0;
    FS_proto.WRITING = 1;
    FS_proto.DONE = 2;
 
    FS_proto.error =
    FS_proto.onwritestart =
    FS_proto.onprogress =
    FS_proto.onwrite =
    FS_proto.onabort =
    FS_proto.onerror =
    FS_proto.onwriteend =
        null;
 
    return saveAs;
}(
       typeof self !== "undefined" && self
    || typeof window !== "undefined" && window
    || this.content
));
// `self` is undefined in Firefox for Android content script context
// while `this` is nsIContentFrameMessageManager
// with an attribute `content` that corresponds to the window
 
if (typeof module !== "undefined" && module.exports) {
  module.exports.saveAs = saveAs;
} else if ((typeof define !== "undefined" && define !== null) && (define.amd !== null)) {
  define("FileSaver.js", function() {
    return saveAs;
  });
}

下载共享漏洞

首先，封装函数以调用FileSaver.js：

var downloadTextFile = function(mobileCode,a) {
    if(!mobileCode) {
        mobileCode = '';
    }
     
    var file = new File([mobileCode], a+".txt", { type: "text/plain;charset=utf-8" });
    saveAs(file);
}

然后，因为该页面使用了jQuery，因此可以直接使用封装好的ajax请求资源链接，书写代码循环遍历漏洞库：

var a = 242;
var timer = setInterval(function(){
  a = a+1;
  if(a>733){clearInterval(timer)}
  $.ajax({method:'GET',url:'/shareData/download/'+a,success:function(res){
    downloadTextFile(res,a)}}
)}, 2000)

a为资源链接后面的数字，经过观察，从242开始，到733结束，结束的数字根据最新的漏洞xml链接而定，鼠标放在链接上，页面左下角就会显示链接：

末尾的2000表示每隔2秒发送一次请求

运行代码

打开CNVD漏洞库的页面
鼠标右键单击检查
点击console控制台
复制上述代码（三段代码合并在一起即可），也可以直接到GitHub下载完整代码复制（其中spider.js为完整js代码，filter为后续过滤结果的代码，欢迎留言点赞打赏提issue点star），粘贴到控制台中，按下回车，代码开始运行
静等下载完毕即可，下载的文件存放在浏览器设定的下载路径里

过滤结果

下载完成后，发现有一些资源为空，大小仅有1kb：

因此，书写python将这些结果过滤掉：

import os

def file_path(path):
	for (root, dirs, files) in os.walk(path):
		for file in files:
			del_small_file(root + '/' + file)

def del_small_file(file_name):
	size = os.path.getsize(file_name)
	file_size = 2 * 1024
	if size < file_size:
		os.remove(file_name)

if __name__ == '__main__':
	path = r'./CNVD'
	file_path(path)

其中，path为存放文件的地址

完成结果

至此，CNVD漏洞库爬取完成，耗时大概10分钟，经过过滤，共成功抓取文件311个：和网页上的原数据对比：数目吻合，表明我们已经爬取了该页面的所有共享数据

you8023 / CNVDSpider