Dev@Free

          zJun's Tech Weblog

          [轉] 破解MySQL的MD5函數

          As per the documentation on MySQL I moved the storage of passwords from using Password() to using MD5(). I read a number of places that stated that this was a method that couldn't be reversed and it was far more secure than the previous method. I was feeling confident that life was about to get a little more secure. While going through my daily RSS feeds and mailing lists for SpikeSource , I happenned upon a thread about someone discussing how easy it was to break MD5 hashes. It was a simple matter of using a brute force algorithm to check all the different combinations.

          Eager to try this out for myself, I did a quick Google and found a Project RainbowCrack which was a Windows/Linux utility that would brute force crack MD5 hashes amongst other secure algorithms. Thinking it would be shrouded in mathematical terms and phrases unfamiliar to me I didn't hold out much hope that I could get it to do what I wanted; to take a sample of passwords that were stored in MySQL database tables using the MD5() function and crack them for me.

          The project builds a number of lookup tables to make the whole process a lot quicker. This in all fairness only took about 18hours to complete on my dual processor 3GHZ machine. After the tables where built it was a simple matter of running a simple command line utility to crack the MD5 hash. Time taken? 1.26seconds! That's how secure MySQL passwords encoded with MD5() are at this precise moment.

          Some sample output from RainbowCrack

          				e:\rainbowcrack-1.2-win>rcrack *.rt -h 7694f4a66316e53c8cdd9d9954bd611d
          md5_loweralpha#1-7_0_2100x8000000_all.rt:
          128000000 bytes read, disk access time: 6.23 s
          verifying the file...
          searching for 1 hash...
          plaintext of 7694f4a66316e53c8cdd9d9954bd611d is qlkjalkj
          cryptanalysis time: 1.52 s
          statistics
          -------------------------------------------------------
          plaintext found:          1 of 1 (100.00%)
          total disk access time:   6.23 s
          total cryptanalysis time: 1.52 s
          total chain walk step:    403651
          total false alarm:        388
          total chain walk step due to false alarm: 579374
          result
          -------------------------------------------------------
          7694f4a66316e53c8cdd9d9954bd611d  qlkjalkj  hex:71
          
          		

          So really, the only reason to store passwords using MD5() would be to discourage the casual hacker, but it is by no means a secure method as some sites would have you believe. It is fair to note that the RainbowCrack documentation states that salted MD5 hashes can't be broken, but MySQL doesn't salt their implementation so it makes no difference here.

          posted on 2007-01-17 16:22 zJun's帛羅閣 閱讀(2594) 評論(0)  編輯  收藏 所屬分類: 數據庫

          導航

          <2007年1月>
          31123456
          78910111213
          14151617181920
          21222324252627
          28293031123
          45678910

          統計

          常用鏈接

          留言簿(15)

          隨筆分類

          隨筆檔案

          相冊

          收藏夾

          博客

          文檔

          站點

          論壇

          搜索

          積分與排名

          最新評論

          閱讀排行榜

          評論排行榜

          主站蜘蛛池模板: 花莲市| 宁蒗| 鄯善县| 芜湖市| 古交市| 德钦县| 通榆县| 辽阳县| 孟州市| 长沙市| 水富县| 毕节市| 夏津县| 湖北省| 曲麻莱县| 阿巴嘎旗| 大姚县| 长垣县| 泌阳县| 胶州市| 大城县| 富宁县| 肥西县| 望都县| 邵阳县| 扎赉特旗| 靖西县| 江都市| 罗江县| 彩票| 安丘市| 兴业县| 河东区| 荆州市| 石渠县| 岗巴县| 呼和浩特市| 贵州省| 三台县| 江孜县| 成都市|