You run hashcat with 707MB memory free.
I run some experiments with hashcat in a Docker container in a VM.
With less then approx. 3GB virtual RAM hashcat stops with Not enough allocatable device memory for this attack..
In some other cases (nvidia GPU, not CPU) running hashcat without the -O option I was able to reduce the memory usage.
Running hashcat in a VM with 4G RAM: ok.
$ echo -n simone | md5sum | cut -d ' ' -f 1 > hash
$ cat hash
47eb752bac1c08c75e30d9624b3e58b7
$ hashcat -m 0 -a 0 -O hash rock.txt
hashcat (v6.2.6) starting
OpenCL API (OpenCL 3.0 PoCL 3.0+debian Linux, None+Asserts, RELOC, LLVM 13.0.1, SLEEF, DISTRO, POCL_DEBUG) - Platform #1 [The pocl project]
============================================================================================================================================
* Device #1: pthread-AMD Ryzen 5 5600G with Radeon Graphics, 1441/2946 MB (512 MB allocatable), 4MCU
Minimum password length supported by kernel: 0
Maximum password length supported by kernel: 31
Hashes: 1 digests; 1 unique digests, 1 unique salts
Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates
Rules: 1
Optimizers applied:
* Optimized-Kernel
* Zero-Byte
* Precompute-Init
* Meet-In-The-Middle
* Early-Skip
* Not-Salted
* Not-Iterated
* Single-Hash
* Single-Salt
* Raw-Hash
Watchdog: Hardware monitoring interface not found on your system.
Watchdog: Temperature abort trigger disabled.
Host memory required for this attack: 0 MB
Dictionary cache built:
* Filename..: rock.txt
* Passwords.: 1000
* Bytes.....: 7784
* Keyspace..: 1000
* Runtime...: 0 secs
The wordlist or mask that you are using is too small.
This means that hashcat cannot use the full parallel power of your device(s).
Unless you supply more work, your cracking speed will drop.
For tips on supplying more work, see: https://hashcat.net/faq/morework
Approaching final keyspace - workload adjusted.
47eb752bac1c08c75e30d9624b3e58b7:simone
Session..........: hashcat
Status...........: Cracked
Hash.Mode........: 0 (MD5)
Hash.Target......: 47eb752bac1c08c75e30d9624b3e58b7
Time.Started.....: Sun Oct 9 11:49:01 2022 (0 secs)
Time.Estimated...: Sun Oct 9 11:49:01 2022 (0 secs)
Kernel.Feature...: Optimized Kernel
Guess.Base.......: File (rock.txt)
Guess.Queue......: 1/1 (100.00%)
Speed.#1.........: 21183 H/s (0.22ms) @ Accel:256 Loops:1 Thr:1 Vec:8
Recovered........: 1/1 (100.00%) Digests (total), 1/1 (100.00%) Digests (new)
Progress.........: 1000/1000 (100.00%)
Rejected.........: 0/1000 (0.00%)
Restore.Point....: 0/1000 (0.00%)
Restore.Sub.#1...: Salt:0 Amplifier:0-1 Iteration:0-1
Candidate.Engine.: Device Generator
Candidates.#1....: 123456 -> cassandra
Running hashcat in a VM with 2G RAM: out of memory.
$ hashcat --potfile-disable -m 0 -a 0 -O hash rock.txt
hashcat (v6.2.6) starting
OpenCL API (OpenCL 3.0 PoCL 3.0+debian Linux, None+Asserts, RELOC, LLVM 13.0.1, SLEEF, DISTRO, POCL_DEBUG) - Platform #1 [The pocl project]
============================================================================================================================================
* Device #1: pthread-AMD Ryzen 5 5600G with Radeon Graphics, 875/1815 MB (256 MB allocatable), 4MCU
Minimum password length supported by kernel: 0
Maximum password length supported by kernel: 31
Hashes: 1 digests; 1 unique digests, 1 unique salts
Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates
Rules: 1
Optimizers applied:
* Optimized-Kernel
* Zero-Byte
* Precompute-Init
* Meet-In-The-Middle
* Early-Skip
* Not-Salted
* Not-Iterated
* Single-Hash
* Single-Salt
* Raw-Hash
Watchdog: Hardware monitoring interface not found on your system.
Watchdog: Temperature abort trigger disabled.
* Device #1: Not enough allocatable device memory for this attack.