L.
Well-Known Member
- Sep 1, 2015
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Versions from 1.98 (December, 2009) to 2.02 (December, 2015) are affected.
The Exploit (PoC)
Exploiting the integer underflow can be used to cause an Off-by-two or an Out of bounds overwrite memory errors. The former error, overwrites up to two bytes right under the username buffer (local variable called login at function grub_auth_check_authentication()), but this area does not contain any usable information to build an attack; actually, it is padding.