Attack mode 6 only uses 1 GPU.
#1
Hi, all.

I'm trying to use attack mode 6 to crack a hash (type -m 18300) and it only uses one GPU. When I use attack mode 0, hashcat uses all 12 GPUs.

Am I missing something, or is hashcat truly limited to only one GPU in attack mode 6?

I'm using hashcat (v5.1.0-1631-gcc4fd48a)
CUDA and NVidia drivers installed from:
cuda_10.2.89_440.33.01_linux.run

NVIDIA-Linux-x86_64-440.64.run

Base OS is Ubuntu Server 18.04

TIA for your assistance and wisdom!

JS
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#2
What is your full command line? How do you determine hashcat only using one device?
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#3
full command line is:

hashcat -m 18300 hash.txt -a 6 wordlist.txt ?a?a?a -w 3 -o output.txt -D 2

I can tell that hashcat is only using one GPU since the status report only shows one GPU with a utilization of 70% and all the rest are at 0%. Also, only that GPU shows any activity in the "Candidates" section: All the rest read like the following:

Candidates.#6....: [Copying]

Also note that there is only one hash in that "hash.txt" file, although there are 14 words in the wordlist.txt file.
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#4
Here's a print of the screen contents. You can see that only the first card is working: The rest are at 0% utilization.

# cat /dev/vcs1
Guess.Queue.Mod..: 1/1 (100.00%)
Speed.#1.........: 21 H/s (0.84ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#2.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#3.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#4.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#5.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#6.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#7.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#8.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#9.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#10.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#11.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#12.........: 0 H/s (0.00ms) @ Accel:16 Loops:256 Thr:1024 Vec:1
Speed.#*.........: 21 H/s
Recovered........: 0/1 (0.00%) Digests
Progress.........: 70686/12003250 (0.59%)
Rejected.........: 0/70686 (0.00%)
Restore.Point....: 0/14 (0.00%)
Restore.Sub.#1...: Salt:0 Amplifier:5049-5050 Iteration:4608-4864
Restore.Sub.#2...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#3...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#4...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#5...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#6...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#7...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#8...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#9...: Salt:0 Amplifier:0-0 Iteration:0-128
Restore.Sub.#10...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#11...: Salt:0 Amplifier:0-0 Iteration:0-256
Restore.Sub.#12...: Salt:0 Amplifier:0-0 Iteration:0-256
Candidates.#1....: $HEX[<<<redacted>>>] -> $HEX[<<<redacted>>>]
Candidates.#2....: [Copying]
Candidates.#3....: [Copying]
Candidates.#4....: [Copying]
Candidates.#5....: [Copying]
Candidates.#6....: [Copying]
Candidates.#7....: [Copying]
Candidates.#8....: [Copying]
Candidates.#9....: [Copying]
Candidates.#10....: [Copying]
Candidates.#11....: [Copying]
Candidates.#12....: [Copying]
Hardware.Mon.#1..: Temp: 32c Fan: 0% Util: 70% Core:1935MHz Mem:6800MHz Bus:1
Hardware.Mon.#2..: Temp: 32c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#3..: Temp: 32c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#4..: Temp: 32c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#5..: Temp: 31c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#6..: Temp: 28c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#7..: Temp: 31c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#8..: Temp: 31c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#9..: Temp: 30c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#10..: Temp: 32c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#11..: Temp: 31c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1
Hardware.Mon.#12..: Temp: 30c Fan: 0% Util: 0% Core:1350MHz Mem:6800MHz Bus:1

[s]tatus [p]ause [b]ypass [c]heckpoint [q]uit =>
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#5
You're not providing enough work to hashcat. Hashcat's performance highly depends on the left part of the attack. In a6 that means the wordlist. As a workaround you can either pipe in the words:

Code:
hashcat  -a 6 wordlist.txt ?a?a?a --stdout | hashcat -m 18300 hash.txt -w 3 -o output.txt -D 2

or use append rules with -a0 -S instead of -a6.
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#6
Fascinating! I will try this tomorrow: Thanks very much.
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#7
That didn't work. What I did to get past the problem was to pipe the output of hashcat -a 3 ?a?a?a to a text file and use that in an Combinator Attack. Now all 12 cards are working.
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