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Comment by sillysaurusx | Hacker News Reader

Yes. This thread is blind-leading-the-blind. Threads against C almost always are.

When I was a pentester, out of more than 50 projects I was on, I always found at least a medium-severity bug (a bug which could allow an attacker to pwn the app using nothing but a web browser). Guess how many of those codebases were written in C? Zero.

The smugness is endemic to people outside of security. I was smug too. There are comments I wrote that I cringe at, looking back. Pentesting changes your perspective on things.

C isn't going away. Yes, let's make it safer (by pentesting). No, it's not a mortal sin to write C. I'll find ways to exploit your webapp regardless of the language.

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>I always found at least a medium-severity bug >Guess how many of those codebases were written in C? Zero.

So, based on those two comments, you have zero data (anecdotal or other) comparing the rate of bugs in C programs versus other languages since you didn't test any C programs.

Code security is not about eliminating bugs but about lowering the rate they show up at since things always get through and money/time is finite. Pen testing doesn't catch everything and many projects that have been tested still yield bugs. There's also a limit to how much money can be spent on testing so using it find (and document, review, etc.) low hanging bugs due to using C means you're more likely to miss a deeper bug.

Or in other words, spending the same effort to pen test a safe language will leave fewer bugs left over than spending it to pen test an unsafe language. So using an unsafe language is still worse.

I'm reminded of Scott Meyers most important design guideline, which I may be paraphrasing slightly, but it goes:

"An API should be easy to use correctly and hard to use incorrectly"

The dumbest link in the chain is always the guy writing the code, not the programming language, and not the machine executing it. So things should be designed in a way that makes it as hard as possible for programmers to make errors.

e: video is here for those who are interested https://www.youtube.com/watch?v=5tg1ONG18H8

That idea is older. Rusty Russell advocated in 2008 that APIs should be "easy to use and hard to misuse".

https://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html

https://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html

Right, this is more broadly applicable than even just APIs or software.

Think about how often you blindly inserted a USB A or B (mini-B, micro-B) plug the wrong way first and had to try again. Why is the wrong way even possible? USB C's plug fixes this.

A huge improvement to railway safety was the invention of Mechanical Interlocking. It was made essentially impossible to set signals in some inherently unsafe ways. When you tried to give a Clear signal to the Express, through a junction a late running Coal Train is already crossing, the huge metal lever you're trying to move to do that won't budge because all your controls are connected via elaborate mechanical interlocking to prevent this mistake. The signal remains at Danger, the Express stops, tragedy is averted.

> Think about how often you blindly inserted a USB A or B (mini-B, micro-B) plug the wrong way first and had to try again. Why is the wrong way even possible? USB C's plug fixes this.

To be honest this isn't really an issue once you notice that the logo side of the USB connector indicates up. I suspect this is mostly an issue because USB connectors have only a tiny self-alignment range (<1 mm), which leads to the "USB exists in a 4D state" meme.

This is a naive and dangerous perspective. You're basically saying that memory safe languages don't solve all problems so it's fine to use unsafe languages.

Don't write code in unsafe languages unless you have to (almost never for new code). Period. You will have some problems either way, but you will have fewer problems in a memory safe language.

Pen testing is not even remotely a good mitigation to depend on against the dangers of a language like C. Its fine to do for defense in depth and to find problems not related to memory safety, but it's no substitute for making a more sensible language choice.

Sudo isn't new code in any sense. "Rewrite the world in memory safe languages" is appealing if you completely discount the time and cost required to do so.

I didn't say that.

And all the new bugs introduced in the process.

That is the classical defense from C camp, going back to the 80's Morris worm.

Can I ask what kind of apps you typically worked on?

A big part of why people make a big deal of C is that there are lots of code bases that have been under a lot of scrutiny from security minded code reviewers and pentesters and still keep on yielding more vulnerabilities. Ie it's hard to make C safe even when you really try and are a good programmer.

In contrast IME most pentesters in the biz work on code bases that have seen much less scrutiny and are often in-house and/or "enterprise" apps whose code was written by people who are probably more domain experts than generally good programmers or security-aware developers...

> When I was a pentester, out of more than 50 projects I was on, I always found at least a medium-severity bug

Perhaps you were a good pentester. More likely the code you attacked was rubbish.

I worked on a relatively important Internet-facing web application for about a decade, it was pen tested by a variety of outfits both when it was owned by a small start-up and when it was owned by a huge corporation.

Good design meant that we never saw any pen tester come anywhere close to "pwn the app" in either its public UI or the APIs which were (by my insistence) publicly accessible rather than wasting our time chasing endless "please change the allowed IP ranges" requests through layers of bureaucracy.

My experience was pen testers would bang on the predictable places, try obvious things, maybe trigger some alarms which I then had to pause - and get nowhere. We'd get back a report that said things like if I put in this nonsense email address I get a different error message than this other nonsense email address. OK, that's nice we'll put it on the backlog, did you find any actual security problems? No.

I'd say that using a memory safe language (Java) helped make that happen, IMNSHO as a very good C programmer for whom writing it in Java was not my first choice (nor was C).

I think most of the people you'll find writing code in C today have decades of experience programming. And I think the knowledge and experience they have makes a huge difference in practice when it comes to security engineering.

In comparison, so much modern javascript is written by junior developers - often without a lot of oversight. Junior developers can't "see" security vulnerabilities yet because they haven't learned to look for them. So I'm not surprised there's lots of critical vulnerabilities in modern software. Many coding bootcamps don't bother to teach any security engineering or best practices, and doing consulting work I've (often by chance) caught a disastrous amount of awful code people have tried to push to production simply because they didn't know any better. A lot of it is really simple stuff - guessable database IDs used as session tokens. JSON objects passed from the browser directly into mongodb. Authentication checks accidentally missing from certain admin dashboard APIs. Passwords and credit card information stored in plaintext, handrolled crypto, and so on.

Given the choice between C code and Rust code written by someone who's been programming for 30 years I expect the rust code would be safer. But if I'm asked to choose between C code written by an experienced engineer and javascript code written by a junior engineer, it wouldn't surprise me if it turned out that the C code was on average still more secure.

20+ year programmers are such a tiny tiny cohort compared to recent ones, I think you underestimate this effect.

(Not that 20 years of experience makes you a decent secure C programmer, but that's a different argument)

I think your vastly underestimating the amount of C and C++ written by junior programmers and you're also overestimating the benefits of decades of C experience.

To be honest, as a group, I find C and C++ programmers (even the ones with decades of experience) to be below average in knowledge and skill.

Ouch.

What experiences have given you that opinion?

Occasionally working with people who have spent decades coding almost solely in C or C++ at one of my old jobs. (Not just one person and not just one team.)

I don't remember too many specifics (it was a while ago) other than being brought onboard and having to introduce the tech lead to the "static" keyword.

So you are saying pentesting makes C safe? I wouldn't be so sure, I've seen several 50k+ LOC projects in C that had vulnerabilities even after several audits.

Is it so wrong to recommend a solution that will kill a good chunk of the problems right at the door?

And FYI, you are being pretty smug here as well. The fact that people criticised unrelated parts of the PR in addition to the relevant parts shouldn't give you a free license to dismiss the bigger criticism.

The idea that pentesting will make code safe is pretty crazy... This is basically the same as saying C code doesn't have safety issues as long as you code carefully.

You would expect developers who put security logic bugs in their code to get C's nuances right while implementing the same application in C?

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