Re: Kernel Rootkits

2005-04-15 Thread Daniel Souza
On 4/15/05, Lee Revell <[EMAIL PROTECTED]> wrote: > On Fri, 2005-04-15 at 11:40 -0700, Daniel Souza wrote: > > A way to "protect" system calls is, after boot a trusted kernel image, > > take a MD5 of the syscalls functions implementations (the opcodes that > > are part of sys_read for example) and

Re: Kernel Rootkits

2005-04-15 Thread Daniel Souza
On 4/15/05, Allison <[EMAIL PROTECTED]> wrote: > Isn't the kernel code segment marked read-only ? How can the module > write into the function text in the kernel ? Shouldn't this cause some > kind of protection fault ? The kernel code segment is totally unacessible to userspace programs, and to ke

Re: Kernel Rootkits

2005-04-15 Thread Lee Revell
On Fri, 2005-04-15 at 11:40 -0700, Daniel Souza wrote: > A way to "protect" system calls is, after boot a trusted kernel image, > take a MD5 of the syscalls functions implementations (the opcodes that > are part of sys_read for example) and store it in a secure place. That's the problem, once the

Re: Kernel Rootkits

2005-04-15 Thread Andre Tomt
Lennart Sorensen wrote: Well you could build a monilithic kernel with module loading turned off entirely, but that doesn't prevent replacing libc which most programs use to make those system calls. As pointed out elsewhere, modules is not the only way to load kernel code live. Modules is just a cl

Re: Kernel Rootkits

2005-04-15 Thread Allison
Isn't the kernel code segment marked read-only ? How can the module write into the function text in the kernel ? Shouldn't this cause some kind of protection fault ? thanks, Allison Lee Revell wrote: > On Fri, 2005-04-15 at 18:15 +, Allison wrote: > > Once these are loaded into the kernel, is

Re: Kernel Rootkits

2005-04-15 Thread Daniel Souza
PS: suckit is not loaded as a kernel module. it uses interrupt gates to allocate kernel memory and install itself in that memory block, patching some syscalls and doing other stuffs. A way to "protect" system calls is, after boot a trusted kernel image, take a MD5 of the syscalls functions impleme

Re: Kernel Rootkits

2005-04-15 Thread Lennart Sorensen
On Fri, Apr 15, 2005 at 06:15:37PM +, Allison wrote: > I got the terminology mixed up. I guess what I really want to know is, > what are the different types of exploits by which rootkits > (specifically the ones that modify the kernel) can get installed on > your system.(other than buffer overf

Re: Kernel Rootkits

2005-04-15 Thread Lee Revell
On Fri, 2005-04-15 at 18:15 +, Allison wrote: > Once these are loaded into the kernel, is there no way the kernel > functions can be protected ? No. If the attacker can load arbitrary code into the kernel, game over. Think about it. Lee - To unsubscribe from this list: send the line "unsubs

Re: Re: Kernel Rootkits

2005-04-15 Thread Petr Baudis
Dear diary, on Fri, Apr 15, 2005 at 08:15:37PM CEST, I got a letter where Allison <[EMAIL PROTECTED]> told me that... > hi, Hello, > I got the terminology mixed up. I guess what I really want to know is, > what are the different types of exploits by which rootkits > (specifically the ones that mo

Re: Kernel Rootkits

2005-04-15 Thread Daniel Souza
In fact, LKM's are not the unique way to make code run in kernel. In fact, we can install a kernel rootkit even when LKM support is disabled. For example, by patching the kernel memory, you can modify the behavior of kernel on-the-fly without restart the machine, just inserting code in the right me

Re: Kernel Rootkits

2005-04-15 Thread Allison
hi, I got the terminology mixed up. I guess what I really want to know is, what are the different types of exploits by which rootkits (specifically the ones that modify the kernel) can get installed on your system.(other than buffer overflow and somebody stealing the root password) I know that Su

Re: Kernel Rootkits

2005-04-15 Thread Lee Revell
On Fri, 2005-04-15 at 13:33 -0400, Malita, Florin wrote: > On Fri, 2005-04-15 at 13:16 -0400, Richard B. Johnson wrote: > > I'm not sure there really are any "kernel" rootkits. You need to be > > root to install a module and you need to be root to replace a ke

Re: Kernel Rootkits

2005-04-15 Thread Malita, Florin
On Fri, 2005-04-15 at 13:16 -0400, Richard B. Johnson wrote: > I'm not sure there really are any "kernel" rootkits. You need to be > root to install a module and you need to be root to replace a kernel > with a new (possibly altered) one. If you are root, you don't

Re: Kernel Rootkits

2005-04-15 Thread Richard B. Johnson
On Fri, 15 Apr 2005, Allison wrote: Hi, I was curious about how kernel rootkits become a part of the kernel ? One way I guess is by inserting a kernel module. And rootkits also manage to hide themselves from rootkit detectors. I'm not sure there really are any "kernel" rootkits.

Kernel Rootkits

2005-04-15 Thread Allison
Hi, I was curious about how kernel rootkits become a part of the kernel ? One way I guess is by inserting a kernel module. And rootkits also manage to hide themselves from rootkit detectors. few questions: 1. Are there any other ways by which rootkits become part of the kernel ? 2. If modules