do you mean that there is a 10-character-long (digits + lower-case letters) random string at the beginning and 1 character (out of a character set of 8 different characters) appended? otherwise this calculation: (36^10) * 8 would make no sense
(10 (decimal) + 26 (lower-case letters)) ^ 10 (10 positions) * 8 (8 different possibilities/chars)
that's how I understand your formula
if the 10 characters are random I wouldn't call it "Some10FixedChars", except if you know this sequence of chars already (like a salt).
It's not obvious from your description which of the 10 + 1 (I assume the total length is 11, but you didn't really clearly say it. it's a little bit confusing with those "Some10FixedChars" and "FIXED" within your mask) is attached to the hash.
My guess is that your plan is to make 8 hashes out of 1 hash (i.e. combine each hash with the 8 possible appended chars). If you do so, you wouldn't need that charset within your mask anymore, therefore this makes no sense
but it should be:
(I assume you also want to use -m 10 = md5 ($pass.$salt), because the 1-out-of-8 character is appended)
In general, I would assume that this is faster
because you don't really seem to have any relation between hash and salt and the (made up) salt is using the whole abcdefgh keyspace.
... but maybe I got it totally wrong and I missinterpreted the Some10FixedChars vs FIXED strings within your examples. You also should have mentioned the total length because it's not obvious if it is 10+1 (11) or 10+8 (18)
(10 (decimal) + 26 (lower-case letters)) ^ 10 (10 positions) * 8 (8 different possibilities/chars)
that's how I understand your formula
if the 10 characters are random I wouldn't call it "Some10FixedChars", except if you know this sequence of chars already (like a salt).
It's not obvious from your description which of the 10 + 1 (I assume the total length is 11, but you didn't really clearly say it. it's a little bit confusing with those "Some10FixedChars" and "FIXED" within your mask) is attached to the hash.
My guess is that your plan is to make 8 hashes out of 1 hash (i.e. combine each hash with the 8 possible appended chars). If you do so, you wouldn't need that charset within your mask anymore, therefore this makes no sense
Code:
-m 20 -1 ?d?l -2 abcdefgh d68236t3236g64a02c8520cd9771d758:Some10FixedChars ?1?1?1?1?1?1?1?1?1?1FIXED?2
but it should be:
Code:
-m 10 -1 ?d?l expanded_hashes_with_abcdefgh_salt.txt ?1?1?1?1?1?1?1?1?1?1
(I assume you also want to use -m 10 = md5 ($pass.$salt), because the 1-out-of-8 character is appended)
In general, I would assume that this is faster
Code:
./hashcat64.bin -a 3 -m 0 -O -w 4 hash.txt -1 ?d?l -2 abcdefgh ?1?1?1?1?1?1?1?1?1?1?2
because you don't really seem to have any relation between hash and salt and the (made up) salt is using the whole abcdefgh keyspace.
... but maybe I got it totally wrong and I missinterpreted the Some10FixedChars vs FIXED strings within your examples. You also should have mentioned the total length because it's not obvious if it is 10+1 (11) or 10+8 (18)