Software based disk encryption not secure enough!
February 22, 2008 by RD · Leave a Comment
Contrary to conventional wisdom, “volatile” semiconductor memory does not entirely lose its contents when power is removed. Both static (SRAM) and dynamic (DRAM) memory retains some information on the data stored in it while power was still applied and they still hold values for a long intervals without power or refresh. This is a known [2] problem for a long long time. However, no one has ever tried (or published) any practical attack on this problem like what Princeton University researchers did.
This DRAM threat goes beyond disk encryption. Any kind of sensitive data such as password, encryption key, credit card information,… in you RAM could be stolen in just a few minutes. Due to the nature of this problem, it’s hard for software based hard disk encryption solution to protect against this attack. Software based solution would be able to try to encrypt/clear the disk key whenever PC goes into inactive state (i.e screen saver, standby, hibernate) but it’s not really practical and/or applicable in some cases. The white paper [1] also offers interesting algorithms & methods to find crypto keys in memory images.
If you’re really care about your information, you should better to change your behavior to unmount encrypted disk and/or power-off your machine (for a while to give the memory enough time to decay) whenever you’re away from your computer if you’re using software based disk encryption and/or to use a hardware based disk encryption solution. FYI, Seagate also has a hardware based hard disk encryption solution ready to use.
Links:
- Lest We Remember: Cold Boot Attacks on Encryption Keys
- Secure Deletion of Data from Magnetic and Solid-State Memory
GSM Monitoring & A5/1 Cracking
February 22, 2008 by RD · Leave a Comment
Hulton & Steve have presented the new fast & cheap method of cracking A5/1 GSM encryption this week at BlackHat DC Security Conference 2008. This is the result of Cracking A5 and GSM scanner project which has been presented at VNSECON 07 by Steve last year.
FYI, GSM monitoring system has always been there for a long time. However, those devices are very expensive (few hundred thousands to millions USD depends on capabilities, number of channels, antenna,…) and only available to government agents.
Links:
- http://blog.washingtonpost.com/securityfix/2008/02/research_may_spell_end_of_mobi.html
- http://www.blackhat.com/html/bh-dc-08/bh-dc-08-speakers.html#Hulton
- http://wiki.thc.org/gsm
- http://wiki.thc.org/cracking_a5
- http://conf.vnsecurity.net/program
hashcrack v1.0
October 9, 2007 by lamer · Leave a Comment
hashcrack is a fast (as fast as OpenSSL allows) hash cracker. It features an additive hash checking to speed up the process. For example, to check for the hashes of abc and abd, hashcrack only computes the hash of ab, then computes one round each for c and d totaling 4 rounds (two for ab, one for c and one for d). This eliminates a good number of rounds if we calculate hashes from the beginning (6 in this case). The longer the key, the more the saving.
A draw back to this feature is it does not work with non-additive hash algorithms. Luckily, popular algorithms, such as SHA-1, RIPEMD160, MD5, are additive.
Compared to vshark (another hash cracker by rd), hashcrack is so much faster. An unscientific benchmark to RIPEMD160-scan the whole 6-character a-zA-Z0-9 space ended in about 6 minutes with hashcrack, and more than 2 hours with vshark. To be fair to vshark, there was another version of hashcrack written in pure Python. It was 6 times slower than vshark.
