David LeBlanc's Web Log
SafeInt moved to github
Has it really been 7 years since I last posted? Yikes - wonder if anyone will see this. The main...
Author: david_leblanc Date: 03/22/2018
Compilers, Integers and Optimizations
I've had a good bit of fun (for some value of fun) with hardening SafeInt against what I consider to...
Author: david_leblanc Date: 12/23/2011
Bugs and Consequences
I've been meaning to write about overzealous compilers, and nice geeky things, but I'm going to use...
Author: david_leblanc Date: 12/22/2011
Another technique for Fixing DLL Preloading attacks
Back in February, 2008, I posted on DLL preloading attacks and how to avoid them here. It seems that...
Author: david_leblanc Date: 08/23/2010
MS10-048 – Getting the Math Right
The Security Research and Defense blog detailed an integer overflow here. The code looks like this:...
Author: david_leblanc Date: 08/10/2010
Acrobat is Getting a Sandbox
We've been helping Adobe to get a sandbox going which is similar to what we used in Office 2010 for...
Author: david_leblanc Date: 07/20/2010
DSig Q & A
I'm going to cover the answers to some of the questions that came in after Shelley answered the...
Author: david_leblanc Date: 05/30/2010
Office 2010 Digital Signatures and XAdES
Shelley Gu, the program manager for Office signatures, has already posted the PM version of what...
Author: david_leblanc Date: 05/30/2010
New “Improved” Site
Hrmph. So they managed to disappear my last post, and now my blog looks really generic. I liked the...
Author: david_leblanc Date: 05/30/2010
You don’t have to be faster than the bear
Note – this post disappeared during the blog upgrade, recovered due to search cache. Just got done...
Author: david_leblanc Date: 05/28/2010
Don’t Use Office RC4 Encryption. Really. Just don’t do it.
Yesterday, a BlackHat Europe presentation on Office 2003 encryption was brought to my attention....
Author: david_leblanc Date: 04/16/2010
Office 2007 SP2 Encryption Settings
Now that we've actually shipped SP2, some of you may be curious about how to use the shiny new...
Author: david_leblanc Date: 05/20/2009
Legacy RC4 Example on Codeplex
Just a quick note on this – a customer had a question about the old RC4 40-bit encryption yesterday,...
Author: david_leblanc Date: 02/06/2009
MS-Offcrypto Example Update
Just a quick note that I've updated the examples. I added an example for the CAPI RC4 encryption...
Author: david_leblanc Date: 01/13/2009
MS-Offcrypto Examples
In response to some questions I've gotten about details of MS-OFFCRYPTO, I've created a CodePlex...
Author: david_leblanc Date: 01/06/2009
Office Crypto KDF Details
I've gotten a couple of questions asking how our key derivation function works. The technique is...
Author: david_leblanc Date: 12/05/2008
New, Improved Office Crypto
If you're enough of an Office crypto geek to stay on top of the most recent changes in MS-OFFCRYPTO,...
Author: david_leblanc Date: 12/04/2008
SafeInt Compiles on gcc!
[update 12-1-08] I now have it completely compiling on gcc, with a test harness that exercises every...
Author: david_leblanc Date: 11/25/2008
Improvements in Office Security
We now have a pretty neat internal web site where I can easily search for CVE entries and bulletin...
Author: david_leblanc Date: 11/17/2008
SafeInt 3 on CodePlex!
I have finally found a stable place to keep SafeInt. It can now be found at...
Author: david_leblanc Date: 09/30/2008
Chrome Getting a Bit Rusty
Put this one in the rant category – I'm honored that Google has been paying attention to my blog and...
Author: david_leblanc Date: 09/12/2008
Why can't you comment?
This is because $#@!!!! spammers can screw up anything. I have to disallow anonymous comments, or I...
Author: david_leblanc Date: 09/08/2008
Ptrdiff_t is evil
Well, not really, but here's a code problem that confounded some really smart devs – and it looks so...
Author: david_leblanc Date: 09/02/2008
Yikes! Vista Security to be Obliterated!
Just picked up this link from Robert Hensing's blog -...
Author: david_leblanc Date: 06/24/2008
Don’t Feed or Tease the Bears…
I've learned over the years to avoid bragging about how much more secure something is than something...
Author: david_leblanc Date: 06/19/2008
More on Checking Allocations
Seems my last post met with some objections – somewhat rightfully so, as I mischaracterized one of...
Author: david_leblanc Date: 04/21/2008
Checking Allocations & Potential for Int Mayhem
Must be synchronicity. I started out the day with a really interesting mail from Chris Wysopal...
Author: david_leblanc Date: 04/16/2008
More Checking for Pointer Math
Someone pointed out that it isn't sufficient to check for whether the pointer math wrapped, but that...
Author: david_leblanc Date: 04/08/2008
Evil Compiler Tricks, and Checking for Pointer Math
My favorite programming geek hobby being integer overflows, this caught my eye – "gcc silently...
Author: david_leblanc Date: 04/04/2008
Visual C++ Defenses and 64-bit
Michael Howard just published a good article here on how Visual C++ features can help protect your...
Author: david_leblanc Date: 03/17/2008
Use of ASLR, NX, etc
Found a really great post by David Maynor here. He points out that various counter-measures aren't...
Author: david_leblanc Date: 03/14/2008
DLL Preloading Attacks
A DLL preloading attack is something that can get you on a lot of different platforms. One of the...
Author: david_leblanc Date: 02/20/2008
Terminating your app on heap corruption
Michael Howard has a FAQ on this here – there's also more information on this and related defenses...
Author: david_leblanc Date: 02/19/2008
HD vs. Blu-ray (2)
I promise I'll get back to security stuff shortly, but over the weekend I ran into a couple of...
Author: david_leblanc Date: 02/18/2008
HD vs. Blu-Ray
OK, so this isn't security related at all, just felt like grumbling about the latest development. If...
Author: david_leblanc Date: 02/15/2008
15 Most Influential Security People
This isn't exactly the list I would have drawn up, and I must be having a bad year, since I'm not on...
Author: david_leblanc Date: 02/14/2008
MulDiv Mayhem
Here's another episode in my ongoing quest to stamp out integer overflows. MulDiv is a Windows API...
Author: david_leblanc Date: 02/07/2008
Unsafe String Handling with strncpy
I recently ran into a piece of code that looked like this: int len = cchIn; strncpy(dest, src, len -...
Author: david_leblanc Date: 02/05/2008
Templatized Min/Max Solved!
I had some time to think about the overall problem, and had originally thought of a functional...
Author: david_leblanc Date: 01/30/2008
Templatized Min/Max is a bad idea!
Ah, back to nice geeky C++ programming topics, which is much more fun than angry customer topics…...
Author: david_leblanc Date: 01/25/2008
A good reason to install SP3
If you haven't already seen this, take a look. A brief quote: Microsoft Security Advisory (947563)...
Author: david_leblanc Date: 01/16/2008
How we know which file formats are used
A reader wrote to ask me how it is that we know what file formats are being opened by users. I can...
Author: david_leblanc Date: 01/14/2008
Office SP3 and File formats
In Office 2007, we changed the default to disable a number of older file formats where we saw very...
Author: david_leblanc Date: 01/04/2008
USB Virtual PC’s
I was browsing the news this morning, and ran across an article - Virtual PCs add new layer of...
Author: david_leblanc Date: 01/03/2008