1. foundation closing

In my submission ： Whether studying safety or engaging in safety , More or less, I have some feelings and sense of mission ！！！

One 、 Basic pass

1.key Where is the ？

The score is :100

Customs clearance address

The problem solving steps

First step ： Visit the customs clearance address , Find out through the question stem key The value is in the current page , We guess from experience that html Comment code .

The second step ： View through developer mode html notes .

The third step ： It can also be done through view-source: To view the page source code , To view the html notes .

Step four ： You can also click the right mouse button to make the page blank , Click to view the source code of the page , To view the html notes .

2. Encrypt it again and you'll get key La ~

The score is :150

The encrypted data is xrlvf23xfqwsxsqf

The problem solving steps

First step ： Because the encrypted data is xrlvf23xfqwsxsqf, Another hint is that you can encrypt it again to get key value , We guess from experience that rot13 encryption , Here are rot13 Explanation of encryption , And look-up tables .

ROT13（ Turn around 13 position ,rotate by 13 places, Sometimes a hyphen in the middle is called ROT-13） It's a simple replacement password . It's a way to hide gossip in English online forums （spoiler）、 Witticism 、 Puzzles, answers and tools for swearing , The purpose is to escape a glimpse of the moderator or .ROT13 Described as “ The magazine puzzle is upside down Usenet Point to point ”.ROT13  It is also a variant of Caesar encryption developed in ancient Rome in the past .

ROT13 Lookup table
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm

The second step ：xrlvf23xfqwsxsqf The results after comparison are as follows .

x–>k

r–>e

l–>y

…

The third step ： Although the second step can be obtained by comparing one by one key Value , But it's too inefficient , So here we use python The script goes on rot13 decode .

#coding=utf-8
import string
rot13Table = string.maketrans( 
    "ABCDEFGHIJKLMabcdefghijklmNOPQRSTUVWXYZnopqrstuvwxyz", 
    "NOPQRSTUVWXYZnopqrstuvwxyzABCDEFGHIJKLMabcdefghijklm")
rot13 = lambda s : string.translate(s, rot13Table)

print rot13("xrlvf23xfqwsxsqf")
#  The secret is ：xrlvf23xfqwsxsqf
#  The result of decryption is ：keyis23ksdjfkfds

3. Guess how many times this has been encrypted ？

The score is :200

The encrypted string is :

Vm0wd2QyUXlVWGxWV0d4V1YwZDRWMVl3WkRSV01WbDNXa1JTVjAxV2JETlhhMUpUVjBaS2RHVkdXbFpOYWtFeFZtcEJlRll5U2tWVWJHaG9UV3N3ZUZadGNFZFpWMDE1VTJ0V1ZXSkhhRzlVVjNOM1pVWmtWMXBFVWxSTmF6RTBWMnRvUjFWdFNrZFhiR2hhWVRKb1JGWldXbUZqVmtaMFVteFNUbUY2UlRGV1ZFb3dWakZhV0ZOcmFHaFNlbXhXVm1wT1QwMHhjRlpYYlVaclVqQTFSMXBGV2xOVWJGcFlaSHBHVjFaRmIzZFdha1poVjBaT2NtRkhhRk5sYlhoWFZtMXdUMVF3TUhoalJscFlZbFZhY1ZadGRHRk5SbFowWlVoa1YwMUVSa1pWYkZKSFZqRmFSbUl6WkZkaGExcG9WakJhVDJOdFJraGhSazVzWWxob1dGWnRNSGRsUjBsNFUydGtXR0pIVWxsWmJGWmhZMnhXYzFWclpGZGlSbkJaV2xWYVQxWlhTbFpYVkVwV1lrWktTRlpxU2tabFZsWlpXa1prYUdFeGNGbFhhMVpoVkRKTmVGcElUbWhTTW5oVVZGY3hiMWRzV1hoWGJYUk9VakZHTlZaWE5VOWhiRXAwVld4c1dtSkhhRlJXTUZwVFZqSkdSbFJzVG1sU2JrSmFWMnhXWVZReFdsaFRiRnBZVmtWd1YxbHJXa3RTUmxweFVWaG9hMVpzV2pGV01uaHJZVWRGZWxGcmJGaFhTRUpJVmtSS1UxWXhXblZWYldoVFlYcFdlbGRYZUc5aU1XUkhWMjVTVGxkSFVsWlVWbHBIVFRGU1ZtRkhPV2hpUlhCNldUQmFjMWR0U2toaFJsSlhUVVp3VkZacVNrZFNiRkp6Vkcxc1UySnJTbUZXTW5oWFdWWlJlRmRzYUZSaVJuQlpWbXRXZDFZeGJISlhhM1JUVW14d2VGVXlkR3RoYlVwV1ZtcGFXbFpXY0doWlZXUkdaVWRPU0U5V1pHaGhNSEJ2Vm10U1MxUXlVa2RVYmtwaFVteEtjRlpxVG05V1ZscEhXVE5vYVUxWFVucFdNV2h2V1ZaS1IxTnVRbFZXTTFKNlZGUkdVMVp0UmtoUFZtaFRUVWhDU2xac1pEUmpNV1IwVTJ0a1dHSlhhR0ZVVnpWdlYwWnJlRmRyZEdwaVZrcElWbGQ0VDJGV1NYcFpNMmhYWVRGd2FGWlVSbFpsUm1SMVUyczFXRkpZUW5oV1YzaHJUa2RHUjFaWVpHaFNWVFZVVlcxNGQyVkdWbGRoUnpsb1RWWndlbFl5Y0VkV01ERjFZVWhLV2xaWFVrZGFWM2hIWTIxS1IxcEdaRTVOUlhCS1ZtMTBVMU14VlhoWFdHaFlZbXhhVmxsclpHOWpSbHB4VkcwNVYxWnRVbGhXVjNNMVZXc3hXRlZyYUZkTmFsWlVWa2Q0WVZKc1RuTmhSbFpYWWxaRmQxWnFRbUZaVm1SSVZXdG9hMUp0YUZSVVZXaERVMnhhYzFwRVVtcE5WMUl3VlRKMGIyRkdTbk5UYkdoVlZteHdNMVl3V25KbFJtUnlaRWR3YVZacmNFbFdiR1EwWVRKR1YxTnVVbEJXUlRWWVZGYzFiMWRHYkhGVGExcHNVbTFTV2xkclZURldNVnB6WTBaV1dGWXpVbkpXVkVaelZqRldjMWRzYUdsV1ZuQlFWa1phWVdReVZrZFdXR3hyVWtWS1dGUldXbmRsVm10M1YyNWtXRkl3VmpSWk1GSlBWMjFGZVZWclpHRldNMmhJV1RJeFMxSXhjRWhpUm1oVFZsaENTMVp0TVRCVk1VMTRWbGhvV0ZkSGFGbFpiWGhoVmpGc2MxcEhPVmRTYlhoYVdUQmFhMkpIU2toVmJHeGhWbGROTVZsV1ZYaFhSbFp5WVVaa1RtRnNXbFZXYTJRMFV6RktjMXBJVmxSaVJscFlXV3RhZDA1c1draGxSMFphVm0xU1IxUnNXbUZWUmxsNVlVaENWbUpIYUVOYVJFWmhZekZ3UlZWdGNFNVdNVWwzVmxSS01HSXlSa2RUYms1VVlrZG9WbFpzV25kTk1WcHlWMjFHYWxacmNEQmFSV1F3VmpKS2NsTnJjRmhpUmxweVdYcEdWbVZXVG5OaVJuQk9UVzFvV1ZkV1VrZGtNa1pIVjJ4V1UySkdjSE5WYlRGVFRWWlZlV042UmxkTlZuQjZXVEJhVjFkR1duTlRhMmhoVWtWYWNsVnFTa3RUVmxKMFlVWk9WMVpHV2pKV2JHTjRUa2RSZVZaclpGZFhSM2h5VldwT1UySXhiSE5XYm1SWFRWWndNRmt3WkVkWFIwcEhZMFpvV2sxSFVuWldNbmhoVjBaV2NscEhSbGRXTVVwUlZsUkNhMUl4U1hsU2EyaHBVbXMxY0ZsVVFuZE5iRnAwVFZSQ1ZrMVZNVFJXVnpWVFZqSkZlVlZ1UmxaaVIxRXdWbTE0YzJNeGNFaFBWbVJUWWtWd1dsWkhlR3BPVmxsNFYyNVNWbUpIYUZoV2FrNU9UVlphV0dNemFGaFNiRnA2V1ZWYWExUnNXWGxoUkVwWFRWWndhRlY2Umt0ak1WSjFWV3hPYVZJeFNuZFdha0pXVFVVeFIxZHJhR3RTTUZwdlZGZHpNV1ZzV1hsT1ZrNW9UVlZ3TUZaWE5VTldNa3BJWVVWU1ZXSllhR2hXYkZwUFZsWktjMVpyTlZkaWEwWXpWbXhqZDAxV1RYaFhhMmhVWWtkb2IxVnFRbUZXYkZwMFpVaGtUazFZUWxsYVZXaExZa1paZUZkcmNGaGhNWEJRVm1wS1JtVkhUa1ZXYkdSVFVsWndlVmRZY0VkV2JWRjNUVlZzYVZJeWFGUlpiR2h2VjFaa1dHVkhPVkpOVlRFMFdUQmFZVll4WkVoaFJsSlZWbTFTVkZwWGVITldiR1J6Vkcxb1YyRXpRWGhXVm1RMFpERlplVk5zYkZaaVIyaG9WV3RXWVdOc1ZuRlRhM1JVVm1zMU1GVnRlRTlpUjBwWllVUlNWMDFYVVhkWFZtUlNaVlphY2xwR1pGaFNNMmg1Vmxkd1ExbFhUa2RXYmxKc1UwZFNjMWxyV25OT1ZuQldZVWQwV0ZKcmJETldiWEJUVjJzeFIxTnNRbGROYWtaSFdsWmFWMk5zY0VoU2JHUk9UVzFvU2xZeFVrcGxSazE0VTFob2FsSlhVbWhWYkZKWFZERldjMkZGVGxSTlZuQXdWRlpTUTFack1WWk5WRkpYWWtkb2RsWXdXbXRUUjBaSVlVWmFUbEp1UW05V2JURTBZekpPYzFwSVNtdFNNMEpVV1d0b1EwNUdXbkpaTTJSUFZteHNORll5TlU5aGJFcFlZVVpzVjJFeFZYaGFSM2h6VmpGYVdXRkdhRk5pUm5BMlYxWldZV0V4VW5OWFdHeG9Va1Z3V0ZSV1duZGhSbFkyVW10MGFrMVdTakZXVjNoRFZqSktSMk5HYkZoV00xSjJWVlJHVTFZeGNFbFViR2hwVmxad1dGWkdXbUZqTURWSFYxaHNUMVpyTlc5VVZsWnpUbFpzVm1GRlRsZGlWWEJKV1ZWV1UxWXdNVmRqUjJoYVRWWndVRmt4V2xkak1XUnlUbFprVGxaWGQzcFdiWGhUVXpBeFNGTlliRk5oTWxKVldXMXpNVlpXYkhKYVJ6bFhZa1p3ZWxZeU5XdFVhekZZWlVaa1YwMXFWbkpXVkVwTFUxWkdjbUZHWkZOTk1taFZWbTF3UzFNeVRuTlVia3BvVW0xU1ZGUlVTbTlpTVZweVZXdDBVMDFYVWtoVk1uaHpXVlpKZWxGc1VsZGhhelYyVmpGYWExZEhWa2hQVmtwT1ZtdHdTVmRVUW1GaU1rWjBWbTVLV0dKSGVGZFpiR2hUVFRGd1YxZHRkR3BpUjFJd1ZERmtiMVl3TVVkaE0yeFhZbFJCZUZscVJscGxSbVJ5VjJ4U2FXSklRbGhXYlhSWFdWZFdjMWR1UmxOaVIxSnhWRlprVTJWc2JGWmFTRTVvVm14d2VWa3dVbUZXTURGWVZWaGtXRlp0VWxOYVZscGhZMnh3UjFwR2FGTk5NbWcxVm14a01GWXhUWGhhUldSV1lrZFNXVmx0TVZOak1WcDBaVWhPVDFadVFsZFpWV1F3VjBaSmQyTkZhRnBOUm5CMlZqSnplRk5IUmtabFJtUk9ZbTFvYjFacVFtRldNazV6WTBWb1UySkhVbGhVVmxaM1ZXeGFjMVZyVGxkaGVsWllWakZvYjJGc1NsaGhSemxXWVd0d2RsWkVSbFprTVZweVpFVTFhVkp1UVhkWGJGWnFUbGRGZDAxV1drNVdSa3BZVm0weGIyUnNXWGRYYlhSVVVqQmFTbFZ0ZUdGaFZrbDRVbGhrVjJKVVJUQlpla3BPWlVaa2RWVnNUbWxTTVVwVlYxZDBWMlF4WkhOWGEyaHNVak5DVUZadE1WTlRSbGw1VGxVNWFHSkZjREJhVldSSFZsWmFWMk5HWkZWV2JIQjZWbXBHWVZkWFJraGpSMnhYVjBWS1NGWnRlR3RPUjBWNFZXNVNVMkpyTlZsWmExcGhWMVphZEUxV1NrNVNiRmt5VlcweFIyRnRSalpXYkdoYVlURndURmxXV2t0ak1rNUhZa1pvVjAweFNtOVhhMUpIWVRGWmVGcElTbWhTTTFKVVZGVmFkMWRXV2tkYVNIQnNVbFJXV0ZadE5WTmhNVW8yWWtaa1ZtSllhSHBVYkZwelZtMUdSbFJzWkdsV1dFSktWMVpXVjFVeFdYZE5WbVJxVWpKb1lWUldXbmRWUm10NFYyeGthazFYVW5sVWJGcHJWR3hhV0dRemNGZGlXR2hVVlhwQmVGTkdTbGxoUjBaVFZqSm9WbGRYZEd0aU1rbDRWbTVTVGxaNmJHRldiWGgzWlZaYWRFMVZaRlZoZWtaWldsVmFhMVl3TVhGV2JrcFhWa1Z3VEZVeFdrZGpiVVpIV2taT1RrMXRhRlpXYlRGM1V6Rk5lVlJ1VGxWaWEzQnhWVzB4YjJOR1ZuUmxTR1JwVFZkU1dGWlhkREJWTURGWFlrUlNWMUl6YUhwWlYzaExaRlpHY2s5V1ZsZGxhMW95Vm1wR1lWbFdTWGhpUkZwVFlsZDRUMVpxUmt0VFZscHhVMVJHVTAxV1ZqVlZNblJoWVd4T1JrNVdaRnBpUmtwSVZtdGFXbVZYVmtoa1IzQnBVbTVDVjFaWE1UUmlNVlY1VWxod1VtSlZXbGhXYlRGU1RVWnNObEp0ZEZOTlYxSXhWbGQ0WVdGSFNrbFJiR1JYWWxSRk1GcEVTbGRqTVdSMVVteE9hVkl4U25oV1JscHJWVEpXYzJKR1dtRlRSVFZ2Vm0xNGQyVldhM2RYYm1SWFRXdHdTVlpIY0ZOV1YwVjVWV3hPWVZac2NHaFpNbmgzVWpGd1NHSkhiRk5YUlVwU1ZtMHdlRTVIUlhoV1dHaGhVbGRTVjFsclduZFdNV3hWVTJ4T2FrMVdjREJhVlZZd1lrZEtSMk5FUWxWV1ZrcFlWbXBCZUZKV1NuTmFSbkJwWW10S1RWWnRNSGhUTVdSWFZtNVdXR0pIVW05WlZFWjNZakZhV0UxVVVtaE5helV3Vm0xMGExbFdTWGxoUnpsVlZrVktURlpYZUdGak1XdDZZVVU1VTJKWWFGcFdhMXB2WWpKR2MxTnNhR2hUUlVwWFdXeG9UbVZHV2tWU2JVWnFUVmRTZWxrd1pEUmhWa3AxVVZoa1dHSkdXbkpWYWtaaFkyc3hWMWR0YkZOU2EzQm9WMVpTUjJReVRuTlhXR1JoVWxoU2NWbHNWVEZTTVZGNFYyMTBhRlp0VWtsWGFrNTNWakpHY2xOdGFGcGxhMXB5VmpCYVUyTnNjRWhTYkU1cFZtdHdWbFl4WkRCWlYxRjNUbFprV0dKc1NrOVdhMVpMV1ZaYWRHVkZaRTlTYkhBd1dsVmFhMVpYU2taalJXeGFUVE5DZVZWR1JUbFFVVDA5

The problem solving steps

First step ： At the end of the string that has been encrypted many times =, We guess from experience that this is base64 encryption , Among them = It plays the role of filling characters .

The second step ： open BurpSuite2021, Get into Decoder modular , Conduct 20 Time base64 Decode to get key value ！！！

4. It is said that MD5 Encryption is secure , Really ？

The score is :200

Ciphertext :e0960851294d7b2253978ba858e24633

The problem solving steps

First step ： By visiting Decrypt online md5 Website , Conduct md5 decode .

5. Racial discrimination

The score is :300

Tips : Xiao Ming visited a website today , It is not allowed Chinese visit ！ It's too much , So Xiaoming decided to go in and find out ！

Customs clearance address

The problem solving steps

First step ： Access via address , It is found that only foreigners are allowed to visit , We guess from experience that we need to use BurpSuite After opening the bag grab , modify HTTP Request... In the package Accept-Language Field , This field is mainly used to tell the server what language we parse , If the field is empty , There is no limit ！！！

The second step ： Browser open proxy , open BurpSuite, Get into Repeater modular , modify Accept-Language Module value is empty .

6.HAHA browser -[UA Request header ]

The score is :200

Tips :

​ It is said that the information security team has recently released a new browser , It's called HAHA browser , Some topics must pass HAHA The browser can answer correctly . Xiao Ming is determined not to pretend HAHA browser , Afraid of a back door , But how to get through this needs to be installed HAHA What can browsers do ？

Customs clearance address

The problem solving steps :

First step ： Pass some questions must pass HAHA The browser can answer correctly , We can guess from experience that it may be necessary BurpSuite Modify... In the request package UA Field , To modify the browser id .( But here we use Firefox Header Editor Plug in to modify the... In the request header UA Field )

The second step ： Turn on Header Editor plug-in unit , Visit website , obtain key value .

7.key Where is it ？-[ Custom response header ]

The score is :200

Tips : Last time, Xiao Ming easily found key, How boring I feel about such a simple topic , So I found key The enhanced , that key Where will you hide this time ？

Customs clearance address

The problem solving steps :

First step ： After accessing the pass through address , Combine the prompt with the echoed content of the page , I found that this is the topic 1 Enhanced version of , And said key The value is here , But we are looking for this position .

The second step ： Obviously ,html Certainly not in the comment code key value , Then it may be in sensitive files 、 In backup file , But no special files were found after scanning .

The third step ： Through the above two steps , Find out html Note no key Value and can't scan sensitive files , Finally, we found in the response header key value .

8.key I can't find it again -[ Intercept 302 Redirect ]

The score is :350

Tips : Xiao Ming can't find it this time key Where have you been? , You can help him find key Do you ？

Customs clearance address

The problem solving steps :

First step ： Access via address , Found a hyperlink , Check the source code and find that the goal of hyperlink jump is search_key.php page , But after we clicked, we found that we actually jumped to index_no_key.php page , Why is that ？

The second step ： Through the phenomena in the first step , We guess that after the user clicks the hyperlink, he will jump to search_key.php, And then they were backstage document Code 302 Redirected to index_no_key.php page , So I missed key value . So we have to find a way to intercept this 302 Redirect , The first reaction is to open BurpSuite Grab the bag , Send in Repeater modular , truncation 302 Redirect , So as to get search_key.php On the page key Value related information .

The third step ：BurpSuite Intercept 302 Reset backward , Discover the real key The value is actually key_is_here_now_.php On the page , We visit the page , To get key value .

9. Pretend to be a login user -[ Request header cookie Logical loopholes in ]

The score is :200

Tips : Xiao Ming came to a website , Still want to key, But it's not funny , Can you help him log in ？

Customs clearance address

The problem solving steps :

First step ： Access via address , Page echo requires login , But there is no login box , We guess from experience that this is just a verification cookie Information login .

The second step ： Use BurpSuite Grab the bag , Send in Repeater modular , Found... In the request field Cookie The value of is Login=0, Obviously, this is a logical loophole , Just change it to 1, Naturally, the login can be successfully verified by the background , To obtain key value .

The third step ： modify cookie The field values for Login=1, To obtain key value .

10. Compare the numbers -[input And maxlength attribute ]

The score is :100

Tips : As long as it is larger than the number on the server ！

Customs clearance address

The problem solving steps :

First step ： Access via address , The page echoes an input field , But you can only enter three digits at most . Because the hint of the title is “ As long as it is larger than the number on the server ！”, So we have to break through the limit on the length of numbers , To submit a value that must be larger than the background number .

The second step ： We visit the source code , Found the following information .

The third step ： Delete maxlength attribute , Submit numbers 99999999999999999999, obtain key value .

11. Local Temptation -[x-forwarded-for Request header ]

The score is :200

Tips :

​ Xiao Ming scanned his beloved Xiao Hong's computer , Found an open 80 port , But when Xiao Ming visited, he found that only local access is allowed , But his beloved Xiaohong dare not let this strange Xiaoming touch her computer , But Xiao Ming really wants to know about Xiao Hong's computer 80 What's the secret behind the port (key)？

Customs clearance address

The problem solving steps :

First step ： Access through prompt , According to the prompt, only local access is allowed 80 port , Our first reaction is to modify the request header x-forwarded-for or client-ip The field values for 127.0.0.1.

The second step ： View source code , Found the problem , So skip the change .

The third step ： If the title is OK , We can set the Firefox browser in this way Header Editor plug-in unit , After the plug-in is enabled , Refresh the page to get key value .

12. I won't let you visit -[robots.txt Sensitive files leaked ]

The score is : 150

Tips :

​ Xiao Ming designed a website , Because they are always attacked by hackers , So this time he put the backstage in a place where no one can find … But it was finally found by hackers , And placed a black page , writes :find you ,no more than 3 secs!

Customs clearance address

The problem solving steps :

First step ： Access via address , Page echo lets us find admin page , however admin.php There is no such thing as ,

The second step ： Through experience we visit robots.txt page （ It can also be obtained through the background directory scanning software robots.txt）, Found a directory /9fb97531fe95594603aff7e794ab2f5f/, Visit the path , Discovery makes us look for login page

The third step ： Access... On the basis of the second step path login.php page , obtain key value .

13. Basic closing summary -[3 Type of question ]

Total score :2350

Question type :3 class

difficulty : Basics

xmind analysis :