Implement SNMPv3 support

[lowSoA]

It was a great addition in #218 to support SNMP (https://zxsecurity.co.nz/research/insights/run-zero-credentials-capture/ awesome work!). This PR implements the support for SNMPv3 that was still outstanding.

This is the current output for SNMPv3, SNMPv1 and SNMPv2c:

The output for SNMPv3 hash can be formatted easily for later cracking, for example with Hashcat. There is a gist which eases this process (with an included hash example from this PR).

Note: as in the original PR #218, pyasn1 is required. Tested with pyasn1==0.4.8 in case it can be added to requirements.txt.

[lowSoA]

For the sake of completeness, this is the output from the gist with the example hash from the screenshot:

$ python formatSNMPv3.py user:308197020103301002034d27bb020300ffe30401010201030431302f041180001f88808106d566db57fd6000000000020100020100040475736572040ce3b25b0e48c5587d5bb1ecf50400304d041180001f88808106d566db57fd60000000000400a736020400d470870201000201003028300d06082b060102010103004301003017060a2b06010603010104010006092b0601060301010505:80001f88808106d566db57fd6000000000:e3b25b0e48c5587d5bb1ecf5
[$] Hashcat format:
user:$SNMPv3$0$45889431$308197020103301002034d27bb020300ffe30401010201030431302f041180001f88808106d566db57fd6000000000020100020100040475736572040c0000000000000000000000000400304d041180001f88808106d566db57fd60000000000400a736020400d470870201000201003028300d06082b060102010103004301003017060a2b06010603010104010006092b0601060301010505$80001f88808106d566db57fd6000000000$e3b25b0e48c5587d5bb1ecf5
    Hashcat mode: 25000

Hashcat output:

$ hashcat -a 0 -m 25000 testsnmp.hash testdict.txt --username
<SNIPPED>
$SNMPv3$0$45889431$308197020103301002034d27bb020300ffe30401010201030431302f041180001f88808106d566db57fd6000000000020100020100040475736572040c0000000000000000000000000400304d041180001f88808106d566db57fd60000000000400a736020400d470870201000201003028300d06082b060102010103004301003017060a2b06010603010104010006092b0601060301010505$80001f88808106d566db57fd6000000000$e3b25b0e48c5587d5bb1ecf5:hashcat1

Session..........: hashcat
Status...........: Cracked
Hash.Mode........: 25000 (SNMPv3 HMAC-MD5-96/HMAC-SHA1-96)
Hash.Target......: $SNMPv3$0$45889431$308197020103301002034d27bb020300...b1ecf5
Time.Started.....: <REDACTED> 2022 (0 secs)
Time.Estimated...: <REDACTED> 2022 (0 secs)
Kernel.Feature...: Pure Kernel
Guess.Base.......: File (testdict.txt)
Guess.Queue......: 1/1 (100.00%)
Speed.#1.........:     1102 H/s (3.53ms) @ Accel:16 Loops:131072 Thr:32 Vec:1
Recovered........: 1/1 (100.00%) Digests (total), 1/1 (100.00%) Digests (new)
Progress.........: 100/100 (100.00%)
Rejected.........: 57/100 (57.00%)
Restore.Point....: 0/100 (0.00%)
Restore.Sub.#1...: Salt:0 Amplifier:0-1 Iteration:917504-1048576
Candidate.Engine.: Device Generator
Candidates.#1....: 123456789 -> hashcat1
Hardware.Mon.#1..: Temp: 47c Util: 98% Core: 212MHz Mem:1230MHz Bus:16

[lgandx]

Merged, thanks for this addition!