What is a return-to-libc exploit?

What is a return-to-libc exploit?

Return-to-libc is an exploit that countered Data Execution Prevention (DEP), which in turn was added as a memory protection scheme in operating systems as a counter to shellcode injection.

What is the main advantage of return-to-libc attack?

Protection from return-to-libc attacks Stack-smashing protection can prevent or obstruct exploitation as it may detect the corruption of the stack and possibly flush out the compromised segment.

How do I find my libc address?

You can easily check this by running gdb–>b main–>info proc mappings a couple of times and comparing the offsets. If they are different, your executable is probably running under ASLR. Assuming there is no ASLR protection, using gdb–>b main–>info proc mappings should give you the base address of the libc SO.

Do Canaries protect against return-to-libc attacks?

No, it doesn’t. It makes it more difficult to perform return-to-libc or ROP but it is definitely no silver bullet against such attacks. First of all, stack canaries only protect against return address smashing through buffer overflows.

What is libc in Linux?

The term “libc” is commonly used as a shorthand for the “standard C library”, a library of standard functions that can be used by all C programs (and sometimes by programs in other languages). Because of some history (see below), use of the term “libc” to refer to the standard C library is somewhat ambiguous on Linux.

What is a ROP chain?

Return Oriented Programming (or ROP) is the idea of chaining together small snippets of assembly with stack control to cause the program to do more complex things.

Where is GDB return address?

To get the location of the stored return address of a specific function, you can place a breakpoint at that function and use the info frame command. Note the saved eip = 0xf7e3ca63 and eip at 0xffffd6fc .

Can Terminator canaries be guessed?

Terminator canaries This type of protection can be bypassed by an attacker overwriting the canary with its known values and the return address with specially-crafted value resulting in a code execution.

What does libc contain?

Select defined external symbols. But really, you don’t need that libc. a contains everything except those things that are explicitly stated to need another library.

Where is libc in Linux?

As for the location, it’s almost certainly going to be in /usr/lib/libc. a and / or /usr/lib/libc.so .

What is ROP buffer overflow?

When a buffer has a certain size, fill the buffer and an add additional code so that the attacker can execute another function in the code or his/her own shellcode. ROP attack: Give a certain input which can override the return address, so that the attacker can control the flow.

How can ROP be defended against?

One common defense for ROP attacks is ASLR which works by randomly moving the segments of a program (includ- ing the text segment) around in memory, preventing the at- tacker from predicting the address of useful gadgets. De- spite ASLR, ROP attacks are still common in the wild for two reasons.

Is EIP the return address?

When a call is executed, the instruction is read from the address in EIP, EIP is incremented past the call instruction and this updated EIP (i.e. the address of the instruction after the call) is pushed onto the stack – it becomes the return address – and the function address is loaded into EIP as the next instruction …

What is RET GDB?

When you use return , GDB discards the selected stack frame (and all frames within it). You can think of this as making the discarded frame return prematurely. If you wish to specify a value to be returned, give that value as the argument to return .

Can Terminator canaries be overwritten?

What is a StackGuard?

StackGuard is a compiler extension that enhances the executable code produced by the compiler so that it detects and thwarts buffer-overflow attacks against the stack. The effect is transparent to the normal function of programs.

Can Terminator Canaries be guessed?

What is the purpose of libc?

DESCRIPTION top. The term “libc” is commonly used as a shorthand for the “standard C library”, a library of standard functions that can be used by all C programs (and sometimes by programs in other languages).

What is libc in Rust?

libc provides all of the definitions necessary to easily interoperate with C code (or “C-like” code) on each of the platforms that Rust supports. This includes type definitions (e.g. c_int ), constants (e.g. EINVAL ) as well as function headers (e.g. malloc ).