SP's blog has a good post today:

:-)

Over at the Matasano Blog :)

Matasano 's Blog quoted my post on Office bugs, and Ivan Arce made some excellent points in the comments:

1. 'They are inherently one-shot. You send a bad file, and while the user might try to open it multiple times, there is no way the attacker can try different values for anything in order to get control.”'

IA: OK. good point but…think about scale & diversity. Even in a targeted attack sending a one-shot client-side exploit against N desktop systems will with one hardcoded address will offset the value of ALSR with some probability of success for a given N. The attacker only needs ONE exploit instance to work in order to break into ONE desktop system, after that it is game over. Client-side bugs are one shot against the same system but not necesarrilly so against several systems in parallel.

Very true, I did overlook this. It also explains the use of really low-value phone-home bots as payload: If you're going to attack in such a "wide" manner, you essentially accept detection as long as you can compromise one of the relevant clients. This means that whatever you are sending will be lost, and therefore you won't send anything more sophisticated than a simple bot.

” 2. There can not be much pre-attack reconnaissance. Fingerprinting server versions is usually not terribly difficult (if time consuming), and usually one can narrow down the exact version (and most of the times the patch level) of a target before actually shooting valuable 0day down the wire. With client side bugs, it is a lot more difficult to know the exact version of a piece of software running on the other side - one probably has to get access to at least one document created by the target to get any data at all, and even this will usually be a rough guesstimate.”

IA: Hmmm not sure about this either. I would argue the desktop systems (clients) leak A LOT more information about themselves than servers and, generally, those leaks are much less controlled and/or controllable and easier to elicit than server leaks. After all, as a general principle, client apps are _designed_ to provide information about themselves.

Not to mention that a lot of information about your desktop systems has *already* leaked and is publicly available on the net now (server logs, emails, documents, stray packets, etc.), you just need to know how and where to look for it.

I disagree on this to an extent. My system leaks information about my mail client because I participate in public forums etc, but the majority of corporate users never gain any visibility outside of the internal network. Most people just don't use mailing lists or usenet etc. So it will be comparatively easy to attack some security officer (hey, I know his exact client version), but the CEO's secretary (which might be a lot more interesting as a target, and less likely to notice her computer is compromised) will be more or less "invisible".

Unbelievable but true

I am decompressing a bit after a few weeks of insane stress and thus I am actually reading blogs. And to my greatest surprise, I ended up reading this one. Now, Oracle security has never interested me ever since I tried to audit it in 2000 and it kept falling over without a fight (or without us really doing anything except sending a few letters to it), but I have to admit that Ms. Davidsons blog has a pretty high entertainment value (at least for me, a morallically degenerate piece of eurotrash full of the afterglow of a once good education system), AND it is refreshing to see someone with a bit of a classical education in IT security (I get picked upon regularly for the fact that I got my Latinum "on the cheap" and know jack shit about old greek - then again, my circle of friends includes a mathematician that claims that he can, by means of listening to a record, tell you in which church in france a certain piece of organ music was played, and hence I am always the loud and stupid one).

Anyhow, given Oracle's horrible code quality, I am very much positively surprised at the quality of Ms. Davidsons blog. And given what most people that have worked with static analysis tools before would describe as a horrible mistake in evaluating tool quality, I would like to mention that mathematics and geometry are part of a classical education. Whoever decided on the right source code analysis tool to use for detecting flaws in Oracle apparently failed that part.

Client Side Exploits, a lot of Office bugs and Vista

I have ranted before about careless use of 0day by seemingly chinese attackers, and I think I have finally understood why someone would use good and nice bugs in such a careless manner:

The bugs are going to expire soon. Or to continue using Dave Aitel's and my terminology: The fish are starting to smell.

ASLR is entering the mainstream with Vista, and while it won't stop any moderately-skilled-but-determined attacker from compromising a server, it will make client side exploits of MSOffice file format parsing bugs a lot harder.

Client-side bugs suffer from a range of difficulties:

1. They are inherently one-shot. You send a bad file, and while the user might try to open it multiple times, there is no way the attacker can try different values for anything in order to get control.
   
2. There can not be much pre-attack reconnaissance. Fingerprinting server versions is usually not terribly difficult (if time consuming), and usually one can narrow down the exact version (and most of the times the patch level) of a target before actually shooting valuable 0day down the wire. With client side bugs, it is a lot more difficult to know the exact version of a piece of software running on the other side - one probably has to get access to at least one document created by the target to get any data at all, and even this will usually be a rough guesstimate.
   

As a result of this, client-side bugs in MSOffice are approaching their expiration date. Not quickly, as most customers will not switch to Vista immediately, but they are showing the first brown spots, and will at some point start to smell.

So you're in a situation where you're sitting on heaps of 0day in MSOffice, which, contrary to Vista, was not the biggest (private sector) pentest ever (This sentence contains two inside jokes, and I hope that those who understand them aren't mad at me :-). What do you do with those that are going to be useless under ASLR ? Well, damn, just fire them somewhere, with some really silly phone-home-bots inside. If they bring back information, fine, if not, you have not actually lost much. The phone-home bots are cheap to develop (in contrast to a decent rootkit) and look amateurish enough as to not provoke your ambassador being yelled at.

If you are really lucky, you might actually get your opponent to devote time and resources to countermeasures against MS Office bugs, in the hope they don't realize that work will be taken care of elsewhere. In the meantime, you hone your skills in defeating ASLR through out-of-defined-memory-read-bugs (see some blog post in the next few days).

On a side note, I am terribly happy today. I've had more luck this week than I deserve.

While we're all talking about the next overflow and think that they have significance in the wider scheme of things, I'll climb on the soapbox for 5 minutes:

We should send peacekeeping troops to Darfour/Sudan. I was strongly opposed to the Iraq war (on the ground that invasion would bring civil war), but I plead my government: Take my taxes and send peacekeeping forces to Sudan. _If_ we have decided that the 'europeans-are-from-venus'-stance is obsolete, we have here a primary example of a conflict where external invasion appears necessary according to almost everybody (except the government in Kartoum).

While I am blogging about strange hobbies: I used to draw a lot, and still appreciate a few comics. Most importantly, local cult hero Jamiri.

Some examples:
http://www.spiegel.de/netzwelt/netzkultur/0,1518,grossbild-650193-422928,00.html

http://www.spiegel.de/netzwelt/netzkultur/0,1518,grossbild-669475-427889,00.html

I am known for odd hobbies and interests, and for a long while, I have been very fascinated with all forms of syncretism, specifically carribbean syncretism.

For various private reasons I am exposed to quite a bit of information about social anthropology, and I usually find the descriptions of odd rites in various societies very amusing and enlightening.

For example, any diagram of multi-family cross-cousin-marriage in some african societies just brings out the graph theory nerd in me, and serious scientific texts debating the difference between endo- and exocannibalism (eat your own tribe vs. eat the other tribe) are a fun diversion from reading dry stuff all day.

Yet I was unprepared for reading about the "Cargo Cult" today. And thinking about it, the sheer fact that a cargo cult developed in Melanesia makes me want to laugh and cry at the same time.

Read it. It's worth it.

Matasano refers to Bleichenbachers' recently published attack. Tremendously short comment:

Anything that does RSA with low exponent is likely attackable. And padding should always be OAEP. ;)

After all the Brouhaha surrounding the work on Apple wireless drivers, I'd like to pitch my two cents:

• Who cares wether this is real or not ? The possibility of breaking NIC drivers (especially in multithreaded kernels) is real, and nobody should be surprised if this happens. Has anyone ever disassembled the pos drivers that come with every cheap electronic USB gadget ? I have my doubts that the QA for NIC drivers is a lot better
• It seems we are not the only ones with a similar problem: http://eprint.iacr.org/2006/303.ps

In the above paper, Eric Filiol says he has broken E0, but does not give any description of the analysis - just a (significant) number of keys that lead to very long strings of zero's or to keystreams with a predefined hamming weight.

I am not decided on the paper yet - read it yesterday evening, jetlagged, over half a bottle of wine. This sort of publishing would be very easy for hash functions -- I would believe anyone that he can build secondary pre-images (or even pre-images) from MD5 if he can give me a string of input that hashes to "thequickbrownfox....".

Now, we just need stuff like that for bugs ;-)

Now with all this noise surrounding the ConsumerReports article where they created 5500 new virus variants, I would really like to get my hands on their sample list to see how VxClass, our malware classification engine, deals with them.

Just to clarify: PaiMei is really good, the previous post was not supposed to be negative or detrimental -- it's definitely cool stuff.

From Matasano:

"The results of one trace can be used to filter subsequent traces. This is huge (in fairness: it’s something that other people, notably Halvar [I believe], have been working on)."

I have to admit that our flash movies that we posted last year in September are mind-numbingly boring, but they do show this sort of stuff ;) -- BinNavi was able to record commentable debug traces since day 1.

http://www.sabre-security.com/products/BinNavi/flash_binnavi_debugger.html
http://www.sabre-security.com/products/BinNavi/flash.html

The entire idea of breakpointing on everything and doing differential debugging dates back to at least a Blackhat presentation in Vegas 2002. Fun stuff, and good to see that with PaiMei there is finally a free framework to do this.

I really need to re-do the BinNavi movies in the next weeks, they really do not do our product any justice any more.

To continue shamelessly plugging my product :-):

"Can I have stack traces for each hit? I know they’re somewhat redundant, but I can graph them to visualize control flow (in particular, to identify event and “parse” loops)."

You can in the next release (scheduled for October) where you can attach arbitrary python scripts to breakpoints and thus do anything to memory you want.

"Symbols. Pedram acknowledges this in his presentation. It didn’t slow me down much not to have them, but it feels weird."

If IDA has them, BinNavi has them.

"I need to be able to click on a hit and see the assembly for it (if there’s a way to click on something and have it pop up in IDA, so much the better)."

Right-click->open subfunction in BinNavi ;)

"Yeah, I need this for non-Windows targets. Remote debugging is apparently coming, which will help. I don’t imagine Pedram’s working on SPARC support (X86 and Win32 has eaten its way pretty thoroughly through the code). Also,"

We have Linux/ptrace support and a (very experimental) WinCE/ARM support.

I promise to redo the movies in the next weeks.

Enough of the advertisement crap.

Cheers,
Halvar

The security world never ceases to amaze me. A few years ago, a few friends of mine would run around security conferences and drunkenly yell "fuzz tester ! fuzz tester !" at people that, well, fuzzed. I found this really hilarious.

What I find amazing though is that fuzzers are now being seriously discussed in whitepapers and even called "artificial intelligence". Folks, can we please NOT do the time warp again ? And can we please start writing about something new ?

On a side note: Since I am a bit of a language nerd, I can't fail to notice that "artificial intelligence" takes a semantically cool twist when mentioned in the same sentence as "yellowcake from africa".

PS: This post is a rant about people that write about fuzzing as a new threat, not about people that write and use fuzzers. Just to clarify :)

I will have an 8-hour layover in Toronto tomorrow -- anyone up for a coffee ?

The article at this link is a bit funny, but if it is true that Materazzi made racial slurs against Zidane, then his headbutt was the ONLY proper answer to that.

Racism on the pitch should not be tolerated under any circumstances, and a healthy team would not tolerate racist remarks from any team member.

If Zidane's reaction was a response to racist remarks, then his headbutt is a symbol for a world cup that did not tolerate racism, and that united people from all over the world instead of dividing them.

On a side note, I am very happy for all the Italians :-) and I'd like to thank my Italian neighbours for having invited us to their place to watch the final.

Enough football, now back to work.

I know that I am going to draw the hate of many people for this post, but I refuse to think less of Zidane for the headbutt against Materazzi. As strange as it sounds, for some reason I am quite convinced that he must have had a good reason for this.

Nobody is mad enough to just headbutt an opponent in the worldcup finals in the last game of a legendary career unless he has a very good reason.

But well.

Question for the Blogosphere: Does anyone know of a real-life crypto protocol in which Diffie-Hellmann over a finite field is used, and that finite field is NOT a prime field ? To be exact, I am looking for examples of real-life crypto using Diffie-Hellmann over GF(p^m) where m > 1.

This Ebay posting for a Yacht that was previously owned by China's Minister of Defense might in fact be a bargain -- I would assume one automatically buys not only the yacht but also some state-of-the-art (of the mid-90's) electronics. I am not sure if that is still worth 2m USD, but still.

I used to read security blogs via http://www.dayioglu.net/planet/ , which now seems down.
It's amusing how quickly I have quit reading blogs since. Funny world.

On bug disclosure and contact with vendors

After reading HDM's blog entry on interaction with MS on one of the recent bugs, I guess I should drop my 2c's worth of opinion into the bowl regarding bug disclosure:

So sometimes I get the urge to find bugs. Then I go out and sometimes I find bugs. Then I usually feel quite happy and sometimes I even write an exploit. I do all this out of personal enjoyment -- I like bugs. I like having to play carambolage billard to get an exploit to work (meaning having to bounce things off of each other in weird angles to get stuff to work). Now, of course, once I am done I have several options on what to do with a bug.

1. Report it to the vendor. This would imply the following steps, all of which take up time and effort better spent on doing something interesting:
   
1. Send mail to their secure@ address, requesting an encryption key. I think it is amusing that some vendors like to call security researchers irresponsible when the default channel for reporting vulnerabilities is unencrypted. That is about as irresponsible as the researchers talking about vulnerabilities on EFNET.
2. Get the encryption key. Spend time writing a description. Send the description, possibly with a PoC.
3. MSRC is a quite skilled bunch, but with almost any other software vendor, a huge back and forth begins now where one has to spend time explaining things to the other side. This involves writing boring things explaining boring concepts etc.
2. Sell it to somebody who pays for vulnerabilities. While this will imply the same lengthy process as mentioned above, at least one can in theory get paid for it. Personally, I wouldn't sell bugs, but that could have several reasons:
1. I am old and lame and can't find bugs that are good enough any more
2. The few bugs that I find are too close to my heart to sell -- each good bug and each good exploit has a story, and I am not so broke that I'd need to sell something that I consider inherently beautiful
3. I don't know the people buying these things. I don't know what they'd do with it. I wouldn't give my dog to a total stranger either.
3. Keep it. Perhabs on a shelf, or in a frame. This implies zero effort on my side. It also gives me the joy of being able to look at it on my wall and think fondly of the story that it belonged to.
   

So in case of 1), after having spent weeks on a bug, I have to spend more time doing something unenjoyable, and get a warm handshake with the words 'thanks for helping secure (the internet/the world/our revenue stream'.
In case 2), I get a warm handshake, some money, and a feeling of guilt for having given my dog to a total stranger.
In case 3), I have something to look at with fond memories and have to invest no time at all into things that I don't find interesting.

What would be your choice ?