john is the first program that pops into the mind when looking at cracking passwords.

Basic Usage

john hashfile --wordlist=/path/to/word/list.txt
john hashfile --wordlist=/path/to/word/list.txt --format=HASHTYPE

ssh2john

ssh2john (requires python2) is python script included within the john package to extract the passphrase hash from an encrypted private key into a hash format john can understand.

python2 /path/to/ssh2john.py private_key > hash-out

Then run john against the hash-out file.

zip2john

zip2john is a python script to extract that the password hash from a zip file into a format john can understand.

/path/to/zip2john out.zip > hash-out

Then run john against the hash-out file.

*2John

The 2 above are the most common in CTF's but john also includes the following scripts.

1password2john.py      axcrypt2john.py     diskcryptor2john.py  hccapx2john.py       krb2john.py          mozilla2john.py           pgpdisk2john.py   sspr2john.py
adxcsouf2john.py       bestcrypt2john.py   dmg2john.py          htdigest2john.py     kwallet2john.py      multibit2john.py          pgpsda2john.py    staroffice2john.py
aem2john.py            bitcoin2john.py     DPAPImk2john.py      ibmiscanner2john.py  lastpass2john.py     neo2john.py               pgpwde2john.py    strip2john.py
aix2john.py            bitshares2john.py   ecryptfs2john.py     ikescan2john.py      libreoffice2john.py  netscreen.py              prosody2john.py   telegram2john.py
andotp2john.py         bitwarden2john.py   ejabberd2john.py     iwork2john.py        lotus2john.py        office2john.py            pse2john.py       tezos2john.py
androidbackup2john.py  bks2john.py         electrum2john.py     kdcdump2john.py      luks2john.py         openbsd_softraid2john.py  ps_token2john.py  truecrypt2john.py
androidfde2john.py     blockchain2john.py  encfs2john.py        keychain2john.py     mac2john-alt.py      openssl2john.py           pwsafe2john.py    vmx2john.py
ansible2john.py        ccache2john.py      enpass2john.py       keyring2john.py      mac2john.py          padlock2john.py           radius2john.py
apex2john.py           cracf2john.py       ethereum2john.py     keystore2john.py     mcafee_epo2john.py   pcap2john.py              signal2john.py
applenotes2john.py     dashlane2john.py    filezilla2john.py    kirbi2john.py        monero2john.py       pem2john.py               sipdump2john.py
aruba2john.py          deepsound2john.py   geli2john.py         known_hosts2john.py  money2john.py        pfx2john.py               ssh2john.py

Formats

descrypt, bsdicrypt, md5crypt, md5crypt-long, bcrypt, scrypt, LM, AFS, 
tripcode, AndroidBackup, adxcrypt, agilekeychain, aix-ssha1, aix-ssha256, 
aix-ssha512, andOTP, ansible, argon2, as400-des, as400-ssha1, asa-md5, 
AxCrypt, AzureAD, BestCrypt, bfegg, Bitcoin, BitLocker, bitshares, Bitwarden, 
BKS, Blackberry-ES10, WoWSRP, Blockchain, chap, Clipperz, cloudkeychain, 
dynamic_n, cq, CRC32, sha1crypt, sha256crypt, sha512crypt, Citrix_NS10, 
dahua, dashlane, diskcryptor, Django, django-scrypt, dmd5, dmg, dominosec, 
dominosec8, DPAPImk, dragonfly3-32, dragonfly3-64, dragonfly4-32, 
dragonfly4-64, Drupal7, eCryptfs, eigrp, electrum, EncFS, enpass, EPI, 
EPiServer, ethereum, fde, Fortigate256, Fortigate, FormSpring, FVDE, geli, 
gost, gpg, HAVAL-128-4, HAVAL-256-3, hdaa, hMailServer, hsrp, IKE, ipb2, 
itunes-backup, iwork, KeePass, keychain, keyring, keystore, known_hosts, 
krb4, krb5, krb5asrep, krb5pa-sha1, krb5tgs, krb5-17, krb5-18, krb5-3, 
kwallet, lp, lpcli, leet, lotus5, lotus85, LUKS, MD2, mdc2, MediaWiki, 
monero, money, MongoDB, scram, Mozilla, mscash, mscash2, MSCHAPv2, 
mschapv2-naive, krb5pa-md5, mssql, mssql05, mssql12, multibit, mysqlna, 
mysql-sha1, mysql, net-ah, nethalflm, netlm, netlmv2, net-md5, netntlmv2, 
netntlm, netntlm-naive, net-sha1, nk, notes, md5ns, nsec3, NT, o10glogon, 
o3logon, o5logon, ODF, Office, oldoffice, OpenBSD-SoftRAID, openssl-enc, 
oracle, oracle11, Oracle12C, osc, ospf, Padlock, Palshop, Panama, 
PBKDF2-HMAC-MD4, PBKDF2-HMAC-MD5, PBKDF2-HMAC-SHA1, PBKDF2-HMAC-SHA256, 
PBKDF2-HMAC-SHA512, PDF, PEM, pfx, pgpdisk, pgpsda, pgpwde, phpass, PHPS, 
PHPS2, pix-md5, PKZIP, po, postgres, PST, PuTTY, pwsafe, qnx, RACF, 
RACF-KDFAES, radius, RAdmin, RAKP, rar, RAR5, Raw-SHA512, Raw-Blake2, 
Raw-Keccak, Raw-Keccak-256, Raw-MD4, Raw-MD5, Raw-MD5u, Raw-SHA1, 
Raw-SHA1-AxCrypt, Raw-SHA1-Linkedin, Raw-SHA224, Raw-SHA256, Raw-SHA3, 
Raw-SHA384, ripemd-128, ripemd-160, rsvp, Siemens-S7, Salted-SHA1, SSHA512, 
sapb, sapg, saph, sappse, securezip, 7z, Signal, SIP, skein-256, skein-512, 
skey, SL3, Snefru-128, Snefru-256, LastPass, SNMP, solarwinds, SSH, sspr, 
Stribog-256, Stribog-512, STRIP, SunMD5, SybaseASE, Sybase-PROP, tacacs-plus, 
tcp-md5, telegram, tezos, Tiger, tc_aes_xts, tc_ripemd160, tc_ripemd160boot, 
tc_sha512, tc_whirlpool, vdi, OpenVMS, vmx, VNC, vtp, wbb3, whirlpool, 
whirlpool0, whirlpool1, wpapsk, wpapsk-pmk, xmpp-scram, xsha, xsha512, ZIP, 
ZipMonster, plaintext, has-160, HMAC-MD5, HMAC-SHA1, HMAC-SHA224, 
HMAC-SHA256, HMAC-SHA384, HMAC-SHA512, dummy, crypt

Git Install

Sometimes the version of john installed as part of teh Operating System may be broked or not be compiled with all the required options. We can install john from Github to work around this

git clone https://github.com/openwall/john.git
cd john/src  
./configure 
make && sudo make install

This will build john under john/run/ where you can run binary or python scripts from without impacting the version already installed.