hashcat stops after about 37 minutes

[patpro]

Hi,

I've got a large number of hashes and for each one I've got a very serious candidate that just need some mask added to get the real password.
So I've made a script that launch hashcat with my candidates (base word + case toggle) against all hashes that share the same "candidate".
The command looks like this:

Code:

./hashcat64.bin -a 6 --increment -m 120 "/foo/bar/hc-tmp/${f}.h" "/foo/bar/hc-tmp/${f}.wl" -1 ?l?u?d ?1?1?1?1?1?1 --potfile-path=/foo/bar/bouclehc.pot --status --status-timer=60 -w 4

Things go smoothly, at least until I reach an increment that brings time above 37 minutes. Strangely, hashcat will just end the session when it reaches about 37-38 minutes. It means it won't finish the last mask (?1?1?1?1?1?1).
Here are two examples:

Code:

Session..........: hashcat
Status...........: Exhausted
Hash.Type........: sha1($salt.$pass)
Hash.Target......: **********************
Time.Started.....: Thu Jul 27 13:12:01 2017 (37 mins, 49 secs)
Time.Estimated...: Sat Jul 29 02:38:36 2017 (1 day, 12 hours)
Guess.Base.......: File (/foo/bar/hc-tmp/haefxsdrgbh:.wl), Left Side
Guess.Mod........: Mask (?1?1?1?1?1?1) [6], Right Side
Guess.Charset....: -1 ?l?u?d, -2 Undefined, -3 Undefined, -4 Undefined
Speed.Dev.#2.....:   431.4 MH/s (0.93ms)
Recovered........: 0/1 (0.00%) Digests, 0/1 (0.00%) Salts
Progress.........: 988836593664/58163441238016 (1.70%)
Rejected.........: 0/988836593664 (0.00%)
Restore.Point....: 1024/1024 (100.00%)
Candidates.#2....: aefxsdrgbhlxNROR -> AEFXSDRGBHt4G080
HWMon.Dev.#2.....: Temp: 71c Fan: 47% Util: 77% Core:1835MHz Mem:4513MHz Bus:16

Started: Thu Jul 27 12:34:55 2017
Stopped: Thu Jul 27 13:49:51 2017

and

Code:

Session..........: hashcat
Status...........: Exhausted
Hash.Type........: sha1($salt.$pass)
Hash.Target......: **********************
Time.Started.....: Thu Jul 27 14:27:15 2017 (37 mins, 59 secs)
Time.Estimated...: Sat Jul 29 03:54:37 2017 (1 day, 12 hours)
Guess.Base.......: File (/foo/bar/hc-tmp/hnadinejame:.wl), Left Side
Guess.Mod........: Mask (?1?1?1?1?1?1) [6], Right Side
Guess.Charset....: -1 ?l?u?d, -2 Undefined, -3 Undefined, -4 Undefined
Speed.Dev.#2.....:   431.3 MH/s (0.93ms)
Recovered........: 0/1 (0.00%) Digests, 0/1 (0.00%) Salts
Progress.........: 988836593664/58163441238016 (1.70%)
Rejected.........: 0/988836593664 (0.00%)
Restore.Point....: 1024/1024 (100.00%)
Candidates.#2....: nadinejamelxNROR -> NADINEJAMEt4G080
HWMon.Dev.#2.....: Temp: 71c Fan: 47% Util: 77% Core:1835MHz Mem:4513MHz Bus:16

Started: Thu Jul 27 13:50:06 2017
Stopped: Thu Jul 27 15:05:15 2017

The script runs in a screen, and is basically a while true loop.

Any idea why hashcat would abort the session after about 37-38 minutes each time?