Editing TrueCrypt (section)

== Security concerns ==

TrueCrypt is vulnerable to various known attacks which are also present in other disk encryption software releases such as [[BitLocker]]. To prevent those, the documentation distributed with TrueCrypt requires users to follow various security precautions.<ref>{{cite web | title =Security Requirements and Precautions | work =TrueCrypt Documentation | publisher =TrueCrypt Foundation | url =http://www.truecrypt.org/docs/?s=security-requirements-and-precautions | archive-url =https://archive.today/20130416034644/http://www.truecrypt.org/docs/?s=security-requirements-and-precautions | url-status =dead | archive-date =16 April 2013 | access-date =24 May 2014 }}</ref> Some of those attacks are detailed below.

=== Encryption keys stored in memory ===
TrueCrypt stores its keys in RAM; on an ordinary personal computer the DRAM will maintain its contents for several seconds after power is cut (or longer if the temperature is lowered). Even if there is some degradation in the memory contents, various algorithms can intelligently recover the keys. This method, known as a [[cold boot attack]] (which would apply in particular to a notebook computer obtained while in power-on, suspended, or screen-locked mode), has been successfully used to attack a file system protected by TrueCrypt.<ref>{{cite web |url=http://www.usenix.org/event/sec08/tech/full_papers/halderman/halderman_html/ |title=Lest We Remember: Cold Boot Attacks on Encryption Keys |author=[[Alex Halderman]] |display-authors=etal}}</ref>

=== Physical security ===
TrueCrypt documentation states that TrueCrypt is unable to secure data on a computer if an attacker physically accessed it and TrueCrypt is used on the compromised computer by the user again (this does not apply to a common case of a stolen, lost, or confiscated computer).<ref>{{cite web | title =Physical Security | work =TrueCrypt Documentation | publisher =TrueCrypt Foundation | url =http://www.truecrypt.org/docs/?s=physical-security | archive-url =https://archive.today/20120913113052/http://www.truecrypt.org/docs/?s=physical-security | url-status =dead | archive-date =13 September 2012 | access-date =24 May 2014 }}</ref> The attacker having physical access to a computer can, for example, install a hardware/software [[keylogger]], a [[Bus mastering|bus-mastering]] device capturing [[RAM|memory]], or install any other malicious [[Hardware Trojan (computing)|hardware]] or [[malware|software]], allowing the attacker to capture unencrypted data (including encryption keys and passwords), or to decrypt encrypted data using captured passwords or encryption keys. Therefore, physical security is a basic premise of a secure system. Attacks such as this are often called "[[Evil Maid attack|evil maid attacks]]".<ref>{{cite web | last =Schneier | first =Bruce | author-link =Bruce Schneier | title ="Evil Maid" Attacks on Encrypted Hard Drives | publisher =Schneier on Security | date =23 October 2009 | url =https://www.schneier.com/blog/archives/2009/10/evil_maid_attac.html | access-date = 24 May 2014 }}</ref>

=== Malware ===
TrueCrypt documentation states that TrueCrypt cannot secure data on a computer if it has any kind of [[malware]] installed. Malware may log keystrokes, thus exposing passwords to an attacker.<ref>{{cite web | title =Malware | work =TrueCrypt Documentation | publisher =TrueCrypt Foundation | url =http://www.truecrypt.org/docs/?s=malware | archive-url =https://archive.today/20120913051130/http://www.truecrypt.org/docs/?s=malware | url-status =dead | archive-date =13 September 2012 | access-date =24 May 2014 }}</ref>

=== The "Stoned" bootkit ===
The "Stoned" [[bootkit]], an [[Master Boot Record|MBR]] [[rootkit]] presented by Austrian software developer Peter Kleissner at the [[Black Hat Briefings|Black Hat]] Technical Security Conference USA 2009,<ref>{{cite web | url = https://www.blackhat.com/presentations/bh-usa-09/KLEISSNER/BHUSA09-Kleissner-StonedBootkit-PAPER.pdf | title = Stoned bootkit White Paper | publisher = Peter Kleissner | work = Black Hat Technical Security Conference USA 2009 | access-date = 5 August 2009 }}</ref><ref>{{cite web | url = https://www.blackhat.com/presentations/bh-usa-09/KLEISSNER/BHUSA09-Kleissner-StonedBootkit-SLIDES.pdf | title = Stoned bootkit Presentation Slides | publisher = Peter Kleissner | work = Black Hat Technical Security Conference USA 2009 | access-date = 5 August 2009 }}</ref> has been shown capable of tampering TrueCrypt's MBR, effectively bypassing TrueCrypt's [[full disk encryption|full volume encryption]].<ref>{{cite web | url = http://www.h-online.com/security/Bootkit-bypasses-hard-disk-encryption--/news/113884 |archive-url=https://web.archive.org/web/20090801080610/http://www.h-online.com/security/Bootkit-bypasses-hard-disk-encryption--/news/113884|archive-date=1 August 2009| title = Bootkit bypasses hard disk encryption | publisher = Heise Media UK Ltd. | work = The H-Security (H-Online.com) | access-date = 5 August 2009 }}</ref><ref>{{cite news |author=David M Williams |date=7 September 2009 |title=The dark side of open source software is Stoned |publisher=iTWire |url=http://www.itwire.com/opinion-and-analysis/the-linux-distillery/27503-the-dark-side-of-open-source-software-is-stoned }}</ref><ref>{{cite web | last =Hunt | first =Simon | title =TrueCrypt vs Peter Kleissner, Or Stoned BootKit Revisited.. | publisher =Simon Hunt | date =4 August 2009 | url =http://simonhunt.wordpress.com/2009/08/04/truecrypt-vs-peter-kleissner-or-stoned-bootkit-revisited | access-date =24 May 2014 }}</ref><ref>{{cite news |author=Uli Ries |date=30 July 2009 |title=Bootkit hebelt Festplattenverschlüsselung aus |language=de |publisher=Heise Online |url=http://www.heise.de/newsticker/meldung/Bootkit-hebelt-Festplattenverschluesselung-aus-748859.html }}</ref><ref>{{cite news |date=30 July 2009 |title=Windows-Hacking: TrueCrypt Verschlüsselung umgangen |language=de |publisher=Gulli News |url=http://www.gulli.com/news/windows-hacking-truecrypt-2009-07-30 }}</ref> Potentially every [[hard disk drive|hard disk]] encryption software is affected by this kind of attack if the encryption software does not rely on hardware-based encryption technologies like [[Trusted Platform Module|TPM]], or if the attack is made with administrative privileges while the encrypted operating system is running.<ref>{{cite web | url = http://www.stoned-vienna.com/downloads/TrueCrypt%20Foundation%20Mail%2018.%20Juli%202009.tif | title = Stoned bootkit attacking TrueCrypt's full volume encryption | publisher = TrueCrypt Foundation mail in response to Peter Kleissner on 18 July 2009 | access-date = 5 August 2009 }}</ref><ref name="TPM support">{{cite web | url = http://www.truecrypt.org/faq#tpm | archive-url = https://archive.today/20130416052646/http://www.truecrypt.org/faq | url-status = dead | archive-date = 16 April 2013 | title = Some encryption programs use TPM to prevent attacks. Will TrueCrypt use it too? | publisher = TrueCrypt Foundation | work = TrueCrypt FAQ | access-date = 24 August 2011 }}</ref>

Two types of attack scenarios exist in which it is possible to maliciously take advantage of this bootkit: in the first one, the user is required to [[Execution (computing)|launch]] the bootkit with administrative privileges once the PC has already booted into Windows; in the second one, analogously to [[hardware keylogger]]s, a malicious person needs physical access to the user's TrueCrypt-encrypted hard disk: in this context this is needed to modify the user's TrueCrypt MBR with that of the Stoned bootkit and then place the hard disk back on the unknowing user's PC, so that when the user boots the PC and types his/her TrueCrypt password on boot, the "Stoned" bootkit intercepts it thereafter because, from that moment on, the Stoned bootkit is loaded before TrueCrypt's MBR in the boot sequence. The first type of attack can be prevented as usual by good security practices, e.g. avoid running non-trusted [[executable]]s with administrative privileges. The second one can be successfully neutralized by the user if he/she suspects that the encrypted hard disk might have been physically available to someone he/she does not trust, by booting the encrypted operating system with TrueCrypt's Rescue Disk instead of booting it directly from the hard disk. With the rescue disk, the user can restore TrueCrypt's MBR to the hard disk.<ref>{{cite web | last =Kleissner | first =Peter | title =TrueCrypt Foundation is a joke to the security industry, pro Microsoft | publisher =Peter Kleissner | date =21 July 2009 | url =http://www.peterkleissner.com/?p=11 | access-date = 5 August 2009 | archive-url = https://web.archive.org/web/20100818024921/http://www.peterkleissner.com/?p=11 | archive-date = 18 August 2010}}</ref>

=== Trusted Platform Module ===
The FAQ section of the TrueCrypt website states that the [[Trusted Platform Module]] (TPM) cannot be relied upon for security, because if the attacker has physical or administrative access to the computer and you use it afterwards, the computer could have been modified by the attacker e.g. a malicious component—such as a hardware keystroke logger—could have been used to capture the password or other sensitive information. Since the TPM does not prevent an attacker from maliciously modifying the computer, TrueCrypt will not support the TPM.<ref name="TPM support" />