CrowBar is somewhat out-of-date. Probably the most comprehensive and up-to-date free password-recovery package is JohnTheRipper. Among many other formats, it can test.dmg's as well. Note that JtR does not 'break' the encryption, it just automates and speeds the process of trying thousands (or millions, or trillions) of dictionary-based.
- I password protected a.dmg file ages ago and stupidly forgot the password but I know some of the numbers that could be in the password and I know of some words that could be in the password. Are there any programs that could crack the password for me? For example a bruteforce program (for mac).
- If you see a Reset Password window with the option to Deactivate Mac, click Deactivate Mac, then click Deactivate to confirm. Enter your new password information, then click Next. If this window shows multiple user accounts, click the Set Password button next to each account name, then enter the new password information for each account.
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Let's cut to the chase right now:
Cracking encrypted disk image, AKA DMG is feasible, but, and there are many buts, is extremely, extremely time consuming.
If you do not remember at all the password, or if you attempt to crack in 'blind mode', you will probably need to teach your kids how to do it: By the time you'll have a fighting chance, you'll be long dead.
Step 1: Write down everything you can remember about the forgotten password, i.e what you could have used, and what you are sure not to have used, i.e. never used a space or a '@' sign.
Step 1a: If you remember enough of your password, or if you are just missing trailing numbers i.e Mypassword???? >> MyPassword1234 and do not remember if it's 1234 or 4321, or 9999, Just use CrowbarDMG and a Wordlist.
For good Wordlists, go here!
If you need to create a specific wordlist (because you remember what you may have used and, most importantly, what you may have not used, go here and look for Wordlists On Demand)
Warning!: CrowbarDMG is slow!
CrowbarDMG is basically a GUI for the hdiutil command
ETA for trying 9999 passwords: About 3 hrs
99,999 passwords: About 30 hrs
999,999 passwords: About 300 hrs Or 12 days ....
Step 2: Do you know how to compile and use John The Ripper? I mean 'use it! including editing Rules, etc?
--> No? Proceed here. Read carefully. Pause. Repeat.
--> Yes! Ok, Sure?
1) Download JTR, version Bleeding Jumbo by Magnum
As of Aug 2013, it's here otherwise here
2) Compile. Don't forget to edit the Makefile and John.conf. Check for CUDA and OMP/MPI RUN. Creating a new Charset? that could be wise...
3) Run dmg2John.py to extract the hash
python [path to file ]dmg2john.py [path to file] myfile.dmg > dmg.txt
4) Edit/Create your rules as needed
5) ./ John etc (Run Baby, run ....)
6) There is always Hashcat (Win/Lin)
7) Because most you have seen, in movies, Hackers cracking an AES within minutes, you'll try without thinking too much about it.
It's going to leave you with a lot of time to read ....
Enjoy ...
8) Without going into too much details, the use of GPU assisted is highly recommended. If you have one of those ones, you'll most likely increase your speed by a factor of 1000, sometimes 10,000 times faster.
☞ Password Cracking AES-256 DMGs and Epic Self-Pwnage
(The Keyword here is: 25 GPU)
☞ 'If you have thought about a new cracking method, It's probably already in JtR'
(Matt Weir) (Quoted liberally)
☞ 'I don't care if the NSA teams up with the KGB, a full random 15Ch long AES is practically unbreakable in a lifetime.
(Matt Weir, Quoted Very Liberally, From circa 2009)
EPAG: Empirical Poke-Around Graph
Markov Probabilities
Disk Image encryption complexity (number of hash iterations) is variable from file to file (from 1000 upto 300 000). The following tables are based on .dmg files with 100 000 iterations.
The final password recovery speed is equal to CPUspeed + GPU(1)speed + ... + GPU(N)speed.
For example: Intel Core i3 + AMD R9 270 = 250 + 3500 = ~3750 p/s.
| CPU: |
|---|
| Instructions Set: |
| Speed p/s: |
| Intel® Core™2 Duo T7500 @ 2.20GHz | Intel® Core™ i3 2100 @ 3.10GHz | Intel® Core™ i3 4130 @ 3.40GHz | Amazon EC2 'c5.large' Xeon® Platinum core |
|---|---|---|---|
| SSE2 | AVX | AVX2 | AVX512 |
| ~50 | ~110 | ~250 | ~300 |
AMD and Nvidia GPUs
Compute units or stream multiprocessors (CU, SM, SMX, SMM) are the main building blocks of GPU calculation power, thus 32xCU GPU card is usually twice as fast as 16xCU GPU card of the same family and architecture running at the same frequency.
You can expect approximately 300-400 p/s performance per every Nvidia SM running at 1Ghz and approximately 150-200 p/s per every AMD CU.
| GT 640 (Kepler) 2xSMX, 1045 MHz | Tesla M60 (Maxwell) 16xSMx, 1150 MHz | GTX 1080 Ti (Pascal) 28xSM, 1580 Mhz | Tesla V100 (Volta) 80xSM, 1380 Mhz |
|---|---|---|---|
| + 670 p/s | + 7 700 p/s | + 22 000 p/s | + 33 000 p/s |
| 670/2/1.05=319 | 7700/16/1.15=418 | 22000/28/1.58=500 | 33000/80/1.38=300 |
Forgot Dmg Password
| HD 6770 (VLIW5) 10xCU, 850 Mhz | R9 270 (GCN 1) 20xCU, 950 MHz | RX 480 (GCN 4) 36xCU, 1260 MHz | RX Vega 64 (GCN 5) 64xCU, 1500 MHz |
|---|---|---|---|
| + 1 750 p/s | + 3 500 p/s | + 7 900 p/s | + 17 000 p/s |
| 1750/10/0.85=205 | 3500/20/0.95=185 | 7900/36/1.26=175 | 17000/64/1.50=180 |
Forgot Dmg Password Recovery
It is important to mention that AMD and NVIDIA architectures are quite different and although AMD per CU performance is lower, there are more CUs per card in a similar price range. Moreover GPU performance is somewhat variable with number of factors including GPU/CPU combination and even a driver version. Please contact us if your recovery speed is noticeable different from the data above.