When you provide a .gz or .zip file as your wordlist, Hashcat builds a dictionary cache by decompressing the file on the fly. The decompressed data is used immediately as it becomes available, without waiting for the entire file to finish decompressing. This streaming approach minimizes memory overhead and startup latency. Hashcat first scans the entire compressed file to gather statistics (such as the total number of passwords and keyspace) and then proceeds with the cracking attack.
7z x -so realhuman_phillipines.7z | hashcat -m 1000 -a 0 ntlm_hash.txt -o cracked.txt --potfile-path my.pot
| Format | Command | |--------|---------| | .gz | gunzip -c list.gz | hashcat ... | | .bz2 | bzcat list.bz2 | hashcat ... | | .xz | xzcat list.xz | hashcat ... | | .7z | 7z x -so list.7z | hashcat ... |
Use Zstd if you have the choice. It offers a better balance between compression ratio and decompression speed than Gzip. Performance Considerations hashcat compressed wordlist
For older Hashcat versions (pre-6.0.0) or unsupported formats like .xz, .bz2, and .zst, the pipeline method is your answer:
Enter the . This article explores the strategies, tools, and commands necessary to feed compressed wordlists (gz, zip, 7z) directly into Hashcat, maintain performance, and build an optimized password cracking rig.
First, becomes prohibitive, especially on cloud instances or laptops used for engagement. Second, and more critically, I/O throughput becomes the limiting factor. Hashcat is designed to saturate GPU compute, but when reading from a slow disk (e.g., a 5400 RPM HDD or a network drive), the GPU spends most of its time idling while waiting for the next batch of passwords. This underutilization can slow cracking attempts by orders of magnitude. Compressed wordlists address both issues by reducing storage requirements and, counterintuitively, increasing effective input speed when paired with on-the-fly decompression. When you provide a
When using native compression support in Hashcat 6+, the tool must decompress the entire wordlist during dictionary cache building. This decompression step occurs before any actual password cracking begins and can take significant time for very large files – as noted earlier, a 2.5TB uncompressed wordlist took approximately three hours to load.
Hashcat natively detects and decompresses the following formats during the initial loading phase: Gzip (.gz) : Widely used for standard wordlists like rockyou.txt.gz ZIP (.zip)
: Hashcat just sees a "stream" of data. If it stops, it has no idea where it was in the original compressed archive. (skip) and Hashcat first scans the entire compressed file to
One optimisation strategy is to pre-process the wordlist with Hashcat itself using the --stdout option, applying rules to generate expanded candidates, then compressing the result. However, users should be cautious with this approach, as the output can become extremely large – potentially exceeding the original wordlist by orders of magnitude.
Problem: A 34 GB uncompressed wordlist (9 GB compressed into .zip ) fails with a "No such file or directory" error when used natively, even though the file exists and permissions are correct.
: This paper analyzes the trade-offs between wordlist size, time, and success rates, which are the primary reasons for employing compression in professional forensic environments. www.markscanlon.co Practical Usage To use a compressed wordlist in current versions of , you can simply point the command to the compressed file: hashcat -m 0 -a 0 [hash_file] [wordlist.zip] how on-the-fly decompression affects GPU cracking speeds compared to raw files? Large zip/gz wordlists gives error - hashcat Forum