Dragan on Security

It seems that bad days came for MD5 and those who based hashes on it. It is possible to create two executable programs with different functionalities with identical MD5 hash. Therefore, it is possible to create malicious executable which has same MD5 hash as regular program. This can be done just by using public Internet information and tools.

Here is short story and list of resources that you can be interested in to try.

In March 2005, Xiaoyun Wang and Hongbo Yu of Shandong University in China published paper “How to Break MD5 and Other Hash Functions” in which they described an algorithm that can find two different sequences of 128 bytes with the same MD5 hash. That article originally was here, but it seems as it not anymore. You can buy it from SpringerLink (here) for price of $25, or download based on subscription to it. There is free Power Point presentation here.

Abstract of paper “How to Break MD5 and Other Hash Functions” says:

MD5 is one of the most widely used cryptographic hash functions nowadays. It was designed in 1992 as an improvement of MD4, and its security was widely studied since then by several authors. The best known result so far was a semi free-start collision, in which the initial value of the hash function is replaced by a non-standard value, which is the result of the attack. In this paper we present a new powerful attack on MD5 which allows us to find collisions efficiently. We used this attack to find collisions of MD5 in about 15 minutes up to an hour computation time. The attack is a differential attack, which unlike most differential attacks, does not use the exclusive-or as a measure of difference, but instead uses modular integer subtraction as the measure. We call this kind of differential a modular differential. An application of this attack to MD4 can find a collision in less than a fraction of a second. This attack is also applicable to other hash functions, such as RIPEMD and HAVAL.

In meantime, Peter Selinger from Department of Mathematics and Statistics, Dalhousie University, published the tool that you can download for free and which he used to create MD5-colliding executable files. He calls it the “evilize” library. This software is based on Patrick Stach’s implementation of Wang and Yu’s algorithm. You can find his original implementation here.

Eduardo Diaz has described a scheme by which two programs could be packed into two archives with identical MD5 hash. A special “extractor” program turns one archive into a “good” program and the other into an “evil” one.

Almost three years ago I had published blog post on MD5 Online Cracking. Also, I have written about NIST new hash competition here and here.

[Thanks to Zeljko for pointing me to this implementation of tool.]

Do you owe cell phone? Yes, of course. Then read this: Cell Phone Spying: Is Your Life Being Monitored?

It says:

It connects you to the world, but your cell phone could also be giving anyone from your boss to your wife a window into your every move.  The same technology that lets you stay in touch on-the-go can now let others tap into your private world — without you ever even suspecting something is awry.

and

You don’t have to plant a CIA-style bug to conduct surveillance any more.  A service called World Tracker lets you use data from cell phone towers and GPS systems to pinpoint anyone’s exact whereabouts, any time — as long as they’ve got their phone on them.

Also:

Dozens of programs are available that’ll turn any cell phone into a high-tech, long-range listening device.  And the scariest part?  They run virtually undetectable to the average eye.

Take, for example, Flexispy.  The service promises to let you “catch cheating wives or cheating husbands” and even “bug meeting rooms.”  Its tools use a phone’s microphone to let you hear essentially any conversations within earshot.  Once the program is installed, all you have to do is dial a number to tap into the phone’s mic and hear everything going on.  The phone won’t even ring, and its owner will have no idea you are virtually there at his side.

Is that legal?

You won’t find it on the flashy front page, but buried a bit further in the site, the company says you’re fine to use their program only “on a phone that you own, for protecting your children,” or for purposes like “archiving data.”  It’s a bit of a contrast from the bold suggestions of “uncover[ing] employee espionage,” “catch[ing] cheating husbands,” and “bug[ging] meeting rooms” that fill the company’s materials.  After a little more explanation, their answer as to the legality of the service ends with a broad statement: “Please consult a qualified lawyer in your country for the correct answer to this question.”

Let me make it easier for you: Once you get into listening in to private conversations without either party’s consent, you’re treading rough water that could sweep you straight into jail.  Whether it’s an employee or a spouse on the receiving end of your mission, neither federal nor state privacy laws take violations lightly in America.  Getting caught could cost you several years behind bars, among other serious penalties.

And can it be detected?

Finding spyware on your phone isn’t easy.  There are dozens of bug detectors available from surveillance companies, but the only true fix is taking your phone to your provider and having them wipe it out altogether.  That will restore the factory settings and clear out any hidden software that’s running on your phone.

Scary, isn’t it? I would strongly suggest to keep your hands far from this.

But also I would suggest to use security software for your cell. For example, there is F-Secure Mobile and I have been using it for some time. Two products can be very helpfull F-Secure Mobile Anti-Virus(TM) and F-Secure Mobile Security(TM). Here are some details:

F-Secure Mobile Anti-Virus(TM)

• F-Secure Mobile Anti-Virus(TM) is easy to use and does not require excess device resources or unnecessary user interaction.
• It automatically scans all files in the background, both in the device and on the memory cards.
• When an infected file is detected it is immediately quarantined to protect all other data in the system.
• The antivirus database is updated invisibly in the background when a data connection is used for emails, web browsing etc.

F-Secure Mobile Security(TM)

• F-Secure Mobile Security enables secure mobile computing by combining an integrated antivirus and firewall.
• Device-recident protection safeguards the mobile device from any type of attack, from intrusion attempts to malware.
• The solution delivers invisible and automated safety through real-time, on-device protection with easy to use firewall rule sets and automatic over-the-air antivirus updates
• F-Secure Mobile Security scans both incoming and outgoing internet/network data packets. It stops malicious, unwanted, harmful, or possibly dangerous packets.
• F-Secure Mobile Security is designed to be easy to use and delivers protection without need for unnecessary user intervention.

We can expect much more to come soon.

Poll “Primary motives for hacking are” which was open on this blog since December 21, 2007 to March 31, 2008 is closed now. Based on answers of visitors, who took opportunity to vote in the poll, main reason why hackers (malicious ones) are attacking is because they take it as intellectual challenge. Next reason is money etc.

Here is summary of results.

As it was said in introductory post for poll, it is based on Australian government Institute of Criminology i.e. its High tech crime centre classification. You can see paper (linked in blog post also) here.

There were polemic about definition of hackers and is that correct to say that hackers are malicious. Many people think that definition of hackers mean that they “wear white hat” i.e. hackers are not driven by malicious motives. However, crackers are ones who “wear black hat” i.e. they are supposed to be malicious, according that opinion. Also, some people mentioned that poll lacks precise definition of hacking and description of hacker and cracker difference for sake of this poll.

This poll is about public opinion - what people think about hackers and their motives, so it was left to opinions and thoughts of everyone and a little bit imprecise (intentionally). :)

You can look into Merriam-Webster’s dictionary definition of hacker – it may be interesting.

If you’ve thought your data are secure on encrypted hard disk, read: Lest We Remember: Cold Boot Attacks on Encryption Keys. Researchers with Princeton University and the Electronic Frontier Foundation (EFF) have found a flaw that renders disk encryption systems useless if an intruder has physical access to your computer - say in the case of a stolen laptop or when a computer is left unattended on a desktop in sleep mode or while displaying a password prompt screen. The attack takes only a few minutes to conduct and uses the disk encryption key that’s stored in the computer’s RAM.

There is also full research paper and YouTube video about this attack.

Abstract says:

Contrary to popular assumption, DRAMs used in most modern computers retain their contents for seconds to minutes after power is lost, even at operating temperatures and even if removed from a motherboard. Although DRAMs become less reliable when they are not refreshed, they are not immediately erased, and their contents persist sufficiently for malicious (or forensic) acquisition of usable full-system memory images. We show that this phenomenon limits the ability of an operating system to protect cryptographic key material from an attacker with physical access. We use cold reboots to mount attacks on popular disk encryption systems — BitLocker, FileVault, dm-crypt, and TrueCrypt — using no special devices or materials. We experimentally characterize the extent and predictability of memory remanence and report that remanence times can be increased dramatically with simple techniques. We offer new algorithms for finding cryptographic keys in memory images and for correcting errors caused by bit decay. Though we discuss several strategies for partially mitigating these risks, we know of no simple remedy that would eliminate them.

[Thanks to colleague Sanida O. for bringing this to my attention].

Be careful, be very careful when use social networking sites! Some social networking sites and some sites that pretend to be social networking, but are marketing profiling sites, may pose huge privacy risk. I will talk here about very popular StubmleUpon which shouldn’t but actually yes.

When you sign for StumbleUpon, you have possibility to email everyone on your mail lists including MSN/hotmail, Yahoo mail, Gmail, AOL, facebook, Outlook, Outlook Express etc and call to join you on your friends list. It is offered through very simple user interface in browser.

If you chose to use this possibility you will need to provide your user name and password for MSN/hotmail, Yahoo mail, Gmail! Seems as password scam, isn’t it.

Much more, if you choose to Outlook i.e. tick radio button next to the Outlook logo it will immediately start downloading add-on called StumbledUpon Contact Import. I hope that you have proper Security level set in your IExplorer; otherwise you will provide them with list of all your Outlook contacts by just one (even accident) click.

If you click on above image, you’ll see larger size image and read message which says “Don’t worry, it’s safe :)”. Message ends by smile, yes… Funny! By reading terms and privacy policy of StumbleUpon, you probably will not find many details about this. It looks like usual benign privacy policy without mentioning high privacy risks that you are exposed to by using this social networking site.

After sending question to support using Web based contact form, automated response arrived which I answered by additional e-mail question stating urgency of response. There is no answer on these questions yet.

There are also other privacy risks of this social networking site including list of friends visible by everyone, visited (stumbled) Web sites, contacts, preferences, messages etc. StumbleUpon offers its toolbar which is considered as spyware by some antispyware scanners.

There is also post on Steve Riley’s blogthat talks about some FaxBox. When you sign up for FaxBox, they ask for your permission to email everyone in your address book (FanBox knows how to talk to most webmail systems).

My recommendation is to avoid clicking on anything suspicious, especially something which will talk to your mail clients, Web based mails and your contacts there. Or to say it stronger: do not click on anything like this never ever!

There is also earlier post on this blog “The Privacy Risks of Social Networking Sites”.

Note:StumbleUpon sent many visitors to my blog and it seems that some stumblers like this blog - thanks all of them. But I have to be honest – StumbleUpon poses privacy risk.

One of main persons behind Microsoft SDL, Michael Howard analyzes recent Symantec and IBM Vulnerabilities in his post on MSDN SDL blog.

Michael says:

The vulnerabilities are not in Symantec code, yet Symantec customers are still open to attack. The issues lie in a small number of file parsers used in many applications created by a third party vendor. As you probably know, file parsing vulnerabilities are very common, and even though the number of such bugs has dropped significantly in Microsoft products, in the past we had many. Thankfully, the SDL’s fuzzing requirements have significantly helped reduce the number of parsing-related vulnerabilities in our products.

And also:

… the same bugs affect IBM’s Lotus Notes 7.0.2 and some other products too.

In summary, Michael says:

Bugs are interesting, you can learn a lot from your own bugs, but also from the bugs in other products. From an SDL perspective, there is nothing new about any of these vulnerabilities. It also appears that the DLLs are not compiled or linked with any other defenses. If I had my way they would be SDL compliant, and have as many defenses as possible as the parser code is an inch away from the Internet, and is used in a mission critical defensive position. What’s interesting to me is how many other products out there consume these giblets? Because those products have security bugs too!

Based on this we can say that Microsoft’s SDL process is becoming very powerful and usable instrument and way to produce more secure software.

I’ve put poll on this blog to find out what is public opinion on primary motives for hacking.  There are six possible choices and you can choose one according your opinion. Answers are based on Australian government Institute of Criminology i.e. its High tech crime centre classification. You can see paper here and vote in box with yellow background at right sidebar.

ZoneAlarm by Check Point, firewall, antivirus and antispyware is tool that I use for quite some time on one of my computers. It offered update to new version 7.0.462.000 today. After installation and starting antispyware scan it detected and considered Windows Live Messenger as Trojan with medium risk.  ZoneAlarm recommended that I should “delete this application immediately because it constitutes security and privacy risks, and has no known usefulness”.

Here is screen shot (censored because of privacy reasons):

ZoneAlarm offered options to quarantine, delete or ignore it. After I selected delete it actually deleted Windows Live Messenger!

I reinstalled messenger, scanned again for spyware and same situation repeated. So we can now say that Check Point firmly considers Windows Live Messenger as Trojan. Some people will say: Not to far from truth, isn’t it? :)

Hopefully Check Point and Microsoft will solve this in mutual talks and confirm messenger as safe software.

An excellent series of blog posts by Microsoft’s Larry Osterman about threat modeling with links to all 13 posts is here. Someone who signed comment as Bill Gates (it might be real Bill?) wrote:

Larry, keep up the good work, I wish we had more people like you in Redmond.

This series of posts is pretty long, detailed, and complicated, but well worth reading.

This is a very interesting question that Steve Riley talked about in recent post on his blog (here). And of course, a number of people have asked him if he is recommending such a stance to other individuals or to organizations. Quickly after that Steve gave more detailed explanation (here). More important is that security decisions always involve tradeoffs. They also (should) involve an intimate understanding of what the users will be doing with their computers.