MS Cites National Security to Justify Closed Source

guacamolefoo writes: "It was recently reported in eWeek that "A senior Microsoft Corp. executive told a federal court last week that sharing information with competitors could damage national security and even threaten the U.S. war effort in Afghanistan. He later acknowledged that some Microsoft code was so flawed it could not be safely disclosed." (Emphasis added.) The follow up from Microsoft is even better: As a result of the flaws, Microsoft has asked the court to allow a "national security" carve-out from the requirement that any code or API's be made public. Microsoft has therefore taken the position that their code is so bad that it must kept secret to keep people from being killed by it. Windows - the Pinto of the 21st century."

Comments

Open source and security - some references

[dwheeler]

Ah yes, the "our APIs and code must be secret or the U.S. will crumble" defense. This is a particularly absurd claim for application programmer interfaces (APIs) - by definition, APIs are disclosed to other developers, so the only reason to "hide" them is to prevent competition. Oddly enough, the products where source code (not just the APIs) is visible have lots of quantitative evidence that they're more secure.

It's already been revealed that some attacker got into Microsoft's network. Also, CD's with Microsoft's source have been released for various reasons over time. I have no trouble believing that some "bad guys" already have the source code. So, how do the rest of us protect ourselves from these bad guys with the source code? And from the bad guys to come who don't have it yet... but will?

As noted in Secure Programming for Linux and Unix HOWTO, section 2.4.2, closing off source code doesn't actually halt attacks anyway. Here's the quote:

It's been argued that a system without source code is more secure because, since there's less information available for an attacker, it should be harder for an attacker to find the vulnerabilities. This argument has a number of weaknesses, however, because although source code is extremely important when trying to add new capabilities to a program, attackers generally don't need source code to find a vulnerability.

First, it's important to distinguish between ``destructive'' acts and ``constructive'' acts. In the real world, it is much easier to destroy a car than to build one. In the software world, it is much easier to find and exploit a vulnerability than to add new significant new functionality to that software. Attackers have many advantages against defenders because of this difference. Software developers must try to have no security-relevant mistakes anywhere in their code, while attackers only need to find one. Developers are primarily paid to get their programs to work... attackers don't need to make the program work, they only need to find a single weakness. And as I'll describe in a moment, it takes less information to attack a program than to modify one.

Generally attackers (against both open and closed programs) start by knowing about the general kinds of security problems programs have. There's no point in hiding this information; it's already out, and in any case, defenders need that kind of information to defend themselves. Attackers then use techniques to try to find those problems; I'll group the techniques into ``dynamic'' techniques (where you run the program) and ``static'' techniques (where you examine the program's code - be it source code or machine code).

In ``dynamic'' approaches, an attacker runs the program, sending it data (often problematic data), and sees if the programs' response indicates a common vulnerability. Open and closed programs have no difference here, since the attacker isn't looking at code. Attackers may also look at the code, the ``static'' approach. For open source software, they'll probably look at the source code and search it for patterns. For closed source software, they might search the machine code (usually presented in assembly language format to simplify the task) for essentially the same patterns. They might also use tools called ``decompilers'' that turn the machine code back into source code and then search the source code for the vulnerable patterns (the same way they would search for vulnerabilities in open source software). See Flake [2001] for one discussion of how closed code can still be examined for security vulnerabilities (e.g., using disassemblers). This point is important: even if an attacker wanted to use source code to find a vulnerability, a closed source program has no advantage, because the attacker can use a disassembler to re-create the source code of the product.

Non-developers might ask ``if decompilers can create source code from machine code, then why do developers say they need source code instead of just machine code?'' The problem is that although developers don't need source code to find security problems, developers do need source code to make substantial improvements to the program. Although decompilers can turn machine code back into a ``source code'' of sorts, the resulting source code is extremely hard to modify. Typically most understandable names are lost, so instead of variables like ``grand_total'' you get ``x123123'', instead of methods like ``display_warning'' you get ``f123124'', and the code itself may have spatterings of assembly in it. Also, _ALL_ comments and design information are lost. This isn't a serious problem for finding security problems, because generally you're searching for patterns indicating vulnerabilities, not for internal variable or method names. Thus, decompilers can be useful for finding ways to attack programs, but aren't helpful for updating programs.

Thus, developers will say ``source code is vital'' (when they intend to add functionality), but the fact that the source code for closed source programs is hidden doesn't protect the program very much.

Microsoft source code is already available...

[RyanFenton]

Austria already has it.

Any U.S. University can apply for it now if they don't already have it.

Many of Microsoft's larger customers have it

I don't see why it would be difficult for any terrorist organization to get it. How can they legitimately argue that it may possible be keep it secret at this point? If it's a national security risk to make the code available, the damage can no longer be avoided.

Ryan Fenton