4 ms·

Keep in mind that many pieces of software are not intended to be resistant to DoS vulnerabilities. For example, any C++ compiler can be made to use exponentiall

by tlb 7y ago

Keep in mind that many pieces of software are not intended to be resistant to DoS vulnerabilities. For example, any C++ compiler can be made to use exponentially large amounts of memory and CPU time by feeding it a specially crafted program; this is not normally considered a DoS vulnerability because you aren't supposed to feed untrusted input to your compiler.

oefrha 7y ago
> any C++ compiler can be made to use exponentially large amounts of memory and CPU time by feeding it a specially crafted program Doesn’t even need to be specially crafted, I wrote a <100 line C++ program to solve a Project Euler problem just yesterday that runs in 0.5s with ~2.5GB of RAM but takes clang++ 50GB of RAM to compile. I could easily tweak a param to make it use any multiple of that to exhaust the RAM on any workstation. Surprised me a bit honestly.
- MHM5000 7y ago
  Off-topic: C++ Newbie here! I would like to see that code and its tweaked version. If at all possible.
  - optimiz3 7y ago
    Quick way to do it would be to calculate some high index in a fibbonacci sequence at compile time using templates.
- anchpop 7y ago
  I think this might be considered a bug if it's a reasonable program
  - a_t48 7y ago
    Probably just over-(ab)use of templates. :)
- oefrha 7y ago
  My program’s much more mundane than using templates as a Turing complete language at compile time. Just a slightly tricky static node pool for a persistent segment tree. Allocating a larger pool causes more RAM usage at compile time, at a 20+x ratio. Probably not gonna share code since I didn’t bother to distill it down to the cause.
user5994461 7y ago
+1 on this. DOS are usually not considered security vulnerabilities. There is really no need to go to extreme length to keep one confidential. Just fill a github issue in the project.
- WinonaRyder 7y ago
  Security vulnerability or not, it's still a DOS. Imagine having just a few requests (like less than 10) to your site consume 100% CPU until the server process is killed or restarted.
- Funnnny 7y ago
  It depends on the exploit but DOS ARE security vulnerabilities and their impact can range from very low to high severity. And please OP don't listen to this and report the vulnerability responsibly even if you're not so sure if it's a security vulnerability or not

by tlb 7y ago

oefrha 7y ago

> any C++ compiler can be made to use exponentially large amounts of memory and CPU time by feeding it a specially crafted program Doesn’t even need to be specially crafted, I wrote a <100 line C++ program to solve a Project Euler problem just yesterday that runs in 0.5s with ~2.5GB of RAM but takes clang++ 50GB of RAM to compile. I could easily tweak a param to make it use any multiple of that to exhaust the RAM on any workstation. Surprised me a bit honestly.

MHM5000 7y ago
Off-topic: C++ Newbie here! I would like to see that code and its tweaked version. If at all possible.
- optimiz3 7y ago
  Quick way to do it would be to calculate some high index in a fibbonacci sequence at compile time using templates.
anchpop 7y ago
I think this might be considered a bug if it's a reasonable program
- a_t48 7y ago
  Probably just over-(ab)use of templates. :)
oefrha 7y ago
My program’s much more mundane than using templates as a Turing complete language at compile time. Just a slightly tricky static node pool for a persistent segment tree. Allocating a larger pool causes more RAM usage at compile time, at a 20+x ratio. Probably not gonna share code since I didn’t bother to distill it down to the cause.

user5994461 7y ago

+1 on this. DOS are usually not considered security vulnerabilities. There is really no need to go to extreme length to keep one confidential. Just fill a github issue in the project.

WinonaRyder 7y ago
Security vulnerability or not, it's still a DOS. Imagine having just a few requests (like less than 10) to your site consume 100% CPU until the server process is killed or restarted.
Funnnny 7y ago
It depends on the exploit but DOS ARE security vulnerabilities and their impact can range from very low to high severity. And please OP don't listen to this and report the vulnerability responsibly even if you're not so sure if it's a security vulnerability or not