SHA-1 Collision
I'm playing with the PDFs created by the SHAttered.io researchers, you can download their paper explaining how they were able to generate a collision which also includes a Base64 encoded tar.bz2 archive of the 2 PDFs files from their site or from here.
Artem Tashkinov, explains here and provides a link to a Pyhton3 script that creates collisions by Robert Xiao.
First, here is how the 2 PDFs look like so you can see they are very different
 |
| Original/Good PDF |
 |
| Collision / BAD PDF |
Both files have the same SHA1 hash:
igor@KYLO-REN:~$ sha1sum good.pdf bad.pdf
d00bbe65d80f6d53d5c15da7c6b4f0a655c5a86a good.pdf
d00bbe65d80f6d53d5c15da7c6b4f0a655c5a86a bad.pdf
d00bbe65d80f6d53d5c15da7c6b4f0a655c5a86a good.pdf
d00bbe65d80f6d53d5c15da7c6b4f0a655c5a86a bad.pdf
igor@KYLO-REN:~$ diff --side-by-side good.pdf.b64 bad.pdf.b64
JVBERi0xLjMKJeLjz9MKCgoxIDAgb2JqCjw8L1dpZHRoIDIgMCBSL0hlaWdod JVBERi0xLjMKJeLjz9MKCgoxIDAgb2JqCjw8L1dpZHRoIDIgMCBSL0hlaWdod
IDQgMCBSL1N1YnR5cGUgNSAwIFIvRmlsdGVyIDYgMCBSL0NvbG9yU3BhY2UgN IDQgMCBSL1N1YnR5cGUgNSAwIFIvRmlsdGVyIDYgMCBSL0NvbG9yU3BhY2UgN
IDggMCBSL0JpdHNQZXJDb21wb25lbnQgOD4+CnN0cmVhbQr/2P/+ACRTSEEtM IDggMCBSL0JpdHNQZXJDb21wb25lbnQgOD4+CnN0cmVhbQr/2P/+ACRTSEEtM
ISGFL+wJIzl1nDmxocY8TJfh//4Bf0bck6a2fgE7ApqqHbJWC0XKZ9aIx/hLj | ISGFL+wJIzl1nDmxocY8TJfh//4Bc0bckWa2fhGPApq2IbJWD/nKZ8yox/hbq
aQkBxWtFwVMK/t+3YDjpcnIv561yjw5JBOBGwjBXD+nUE5ir4S71vJQr4zVCp | qQkB1d9FwU8m/t+z3DjpasIv571yjw5FvOBG0jxXD+sUE5i7VS71oKgr4zH+p
rDUU503cDyzBqHTNDHgwWiFWZGEwl4lga9C/P5jNqARGKaEAAAAAAAAAAAAAA | rDUA603cDezBqGR5DHgsdiFWYN0wl5HQa9CvP5jNpLxGKbEAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAP/gABBKRklGAAEBAQBIAEgAAP/+ABNDcmVhdGVkIHdpdGggR0lNUP/bA AAAAAP/gABBKRklGAAEBAQBIAEgAAP/+ABNDcmVhdGVkIHdpdGggR0lNUP/bA
AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA
AEMBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA AEMBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA
AQEBAQEBAQEBAf/CABEIAAgACAMBEQACEQEDEQH/xAAUAAEAAAAAAAAAAAAAA AQEBAQEBAQEBAf/CABEIAAgACAMBEQACEQEDEQH/xAAUAAEAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAACf/+AAb//gAv/9oADAMBAAIQAxAAAAFTncUf/8QAF AAAAAAAAAAAAAAAAAAAACf/+AAb//gAv/9oADAMBAAIQAxAAAAFTncUf/8QAF
AAAAAAAAFib//gAG//4AM//aAAgBAQABBQKpU//EAB8RAAADCQAAAAAAAAAAA AAAAAAAAFib//gAG//4AM//aAAgBAQABBQKpU//EAB8RAAADCQAAAAAAAAAAA
Y2WGlf/+AAb//gBB/9oACAEDAQE/AZqKpW1TO7I4c55hIWa5DmBb/8QAHhEAA Y2WGlf/+AAb//gBB/9oACAEDAQE/AZqKpW1TO7I4c55hIWa5DmBb/8QAHhEAA
AAAAABQVFxMnRWNlhZT//gAG//4AQP/aAAgBAgEBPwGYThVVwVW2bNw+BKIaR AAAAABQVFxMnRWNlhZT//gAG//4AQP/aAAgBAgEBPwGYThVVwVW2bNw+BKIaR
AAAAAAAAAAAAAAAAFBMAEhUWRGJkhZT//gAG//4AM//aAAgBAQAGPwKtmk2xd AAAAAAAAAAAAAAAAFBMAEhUWRGJkhZT//gAG//4AM//aAAgBAQAGPwKtmk2xd
FBABAAAAAAAAAAAAAAAAAAAAAP/+AAb//gAS/9oACAEBAAE/IWAB//4ABv/+A FBABAAAAAAAAAAAAAAAAAAAAAP/+AAb//gAS/9oACAEBAAE/IWAB//4ABv/+A
AAAAEB//xAAUEQEAAAAAAAAAAAAAAAAAAAAA//4ABv/+ACj/2gAIAQMBAT8Qa AAAAEB//xAAUEQEAAAAAAAAAAAAAAAAAAAAA//4ABv/+ACj/2gAIAQMBAT8Qa
AAAAAAAAAAAAAAAA//4ABv/+ACj/2gAIAQIBAT8Qa8f/xAAUEAEAAAAAAAAAA AAAAAAAAAAAAAAAA//4ABv/+ACj/2gAIAQIBAT8Qa8f/xAAUEAEAAAAAAAAAA
Bv/+ABT/2gAIAQEAAT8QFT//2UFOR0X/4AAQSkZJRgABAQEASABIAAD//gATQ Bv/+ABT/2gAIAQEAAT8QFT//2UFOR0X/4AAQSkZJRgABAQEASABIAAD//gATQ
IEdJTVD/2wBDAAEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA IEdJTVD/2wBDAAEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA
AQEBAQEBAQEBAQEBAQEBAQH/2wBDAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA AQEBAQEBAQEBAQEBAQEBAQH/2wBDAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBA
AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/wgARCAAIAAgDAREAAhEBA AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/wgARCAAIAAgDAREAAhEBA
AAAAAAAAAAAAAAAACf/EABUBAQEAAAAAAAAAAAAAAAAAAAYH/9oADAMBAAIQA AAAAAAAAAAAAAAAACf/EABUBAQEAAAAAAAAAAAAAAAAAAAYH/9oADAMBAAIQA
ABQQAQAAAAAAAAAAAAAAAAAAAAD/2gAIAQEAAQUCf//EABgRAAIDAAAAAAAAA ABQQAQAAAAAAAAAAAAAAAAAAAAD/2gAIAQEAAQUCf//EABgRAAIDAAAAAAAAA
/9oACAEDAQE/Ad/b/Z/P/8QAGBEAAgMAAAAAAAAAAAAAAAAAAPA2prb/2gAIA /9oACAEDAQE/Ad/b/Z/P/8QAGBEAAgMAAAAAAAAAAAAAAAAAAPA2prb/2gAIA
xAAYEAACAwAAAAAAAAAAAAAAAAAA8Ddnp//aAAgBAQAGPwKpnJmJj//EABQQA xAAYEAACAwAAAAAAAAAAAAAAAAAA8Ddnp//aAAgBAQAGPwKpnJmJj//EABQQA
AAAAAAD/2gAIAQEAAT8hf//aAAwDAQACAAMAAAAQH//EABQRAQAAAAAAAAAAA AAAAAAD/2gAIAQEAAT8hf//aAAwDAQACAAMAAAAQH//EABQRAQAAAAAAAAAAA
AQMBAT8QD//EABQRAQAAAAAAAAAAAAAAAAAAAAD/2gAIAQIBAT8QD//EABQQA AQMBAT8QD//EABQRAQAAAAAAAAAAAAAAAAAAAAD/2gAIAQIBAT8QD//EABQQA
AAAAAAD/2gAIAQEAAT8QD//ZCmVuZHN0cmVhbQplbmRvYmoKCjIgMCBvYmoKO AAAAAAD/2gAIAQEAAT8QD//ZCmVuZHN0cmVhbQplbmRvYmoKCjIgMCBvYmoKO
MCBvYmoKOAplbmRvYmoKCjQgMCBvYmoKL1hPYmplY3QKZW5kb2JqCgo1IDAgb MCBvYmoKOAplbmRvYmoKCjQgMCBvYmoKL1hPYmplY3QKZW5kb2JqCgo1IDAgb
bmRvYmoKCjYgMCBvYmoKL0RDVERlY29kZQplbmRvYmoKCjcgMCBvYmoKL0Rld bmRvYmoKCjYgMCBvYmoKL0RDVERlY29kZQplbmRvYmoKCjcgMCBvYmoKL0Rld
YmoKCjggMCBvYmoKMTY5MwplbmRvYmoKCjkgMCBvYmoKPDwKICAvVHlwZSAvQ YmoKCjggMCBvYmoKMTY5MwplbmRvYmoKCjkgMCBvYmoKPDwKICAvVHlwZSAvQ
YWdlcyAxMCAwIFIKPj4KZW5kb2JqCgoKMTAgMCBvYmoKPDwKICAvVHlwZSAvU YWdlcyAxMCAwIFIKPj4KZW5kb2JqCgoKMTAgMCBvYmoKPDwKICAvVHlwZSAvU
bnQgMQogIC9LaWRzIFsxMSAwIFJdCj4+CmVuZG9iagoKMTEgMCBvYmoKPDwKI bnQgMQogIC9LaWRzIFsxMSAwIFJdCj4+CmVuZG9iagoKMTEgMCBvYmoKPDwKI
ZQogIC9QYXJlbnQgMTAgMCBSCiAgL01lZGlhQm94IFswIDAgOCA4XQogIC9Dc ZQogIC9QYXJlbnQgMTAgMCBSCiAgL01lZGlhQm94IFswIDAgOCA4XQogIC9Dc
OCA4XQogIC9Db250ZW50cyAxMiAwIFIKICAvUmVzb3VyY2VzCiAgPDwKICAgI OCA4XQogIC9Db250ZW50cyAxMiAwIFIKICAvUmVzb3VyY2VzCiAgPDwKICAgI
L0ltMCAxIDAgUj4+CiAgPj4KPj4KZW5kb2JqCgoxMiAwIG9iago8PC9MZW5nd L0ltMCAxIDAgUj4+CiAgPj4KPj4KZW5kb2JqCgoxMiAwIG9iago8PC9MZW5nd
YW0KcQogIDggMCAwIDggMCAwIGNtCiAgL0ltMCBEbwpRCmVuZHN0cmVhbQplb YW0KcQogIDggMCAwIDggMCAwIGNtCiAgL0ltMCBEbwpRCmVuZHN0cmVhbQplb
ZgowIDEzIAowMDAwMDAwMDAwIDY1NTM1IGYgCjAwMDAwMDAwMTcgMDAwMDAgb ZgowIDEzIAowMDAwMDAwMDAwIDY1NTM1IGYgCjAwMDAwMDAwMTcgMDAwMDAgb
MSAwMDAwMCBuIAowMDAwMDAxODc5IDAwMDAwIG4gCjAwMDAwMDE4OTcgMDAwM MSAwMDAwMCBuIAowMDAwMDAxODc5IDAwMDAwIG4gCjAwMDAwMDE4OTcgMDAwM
MTkyMiAwMDAwMCBuIAowMDAwMDAxOTQ1IDAwMDAwIG4gCjAwMDAwMDE5NzIgM MTkyMiAwMDAwMCBuIAowMDAwMDAxOTQ1IDAwMDAwIG4gCjAwMDAwMDE5NzIgM
MDAwMTk5OSAwMDAwMCBuIAowMDAwMDAyMDIwIDAwMDAwIG4gCjAwMDAwMDIwN MDAwMTk5OSAwMDAwMCBuIAowMDAwMDAyMDIwIDAwMDAwIG4gCjAwMDAwMDIwN
MDAwMDAwMjE0MiAwMDAwMCBuIAowMDAwMDAyMzA5IDAwMDAwIG4gCgp0cmFpb MDAwMDAwMjE0MiAwMDAwMCBuIAowMDAwMDAyMzA5IDAwMDAwIG4gCgp0cmFpb
IDkgMCBSIC9TaXplIDEzPj4KCnN0YXJ0eHJlZgoyMzkxCiUlRU9GCg== IDkgMCBSIC9TaXplIDEzPj4KCnN0YXJ0eHJlZgoyMzkxCiUlRU9GCg==
Only 3 lines of the Base64 differ (marked in red), and there's where the magic happens.
SHAttered already took it's first victim, WebKit's Apache SVN, you can read about it here
This means that is not only about SSL/TLS Certificates and encryption, it's also about potential DoS of systems that are depended on SHA1 to do deduping or version control for example.
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