Vulnerabilities > CVE-2012-6066 - Improper Authentication vulnerability in Freesshd 1.2.1/1.2.2/1.2.6
Attack vector
NETWORK Attack complexity
MEDIUM Privileges required
NONE Confidentiality impact
COMPLETE Integrity impact
COMPLETE Availability impact
COMPLETE Summary
freeSSHd.exe in freeSSHd through 1.2.6 allows remote attackers to bypass authentication via a crafted session, as demonstrated by an OpenSSH client with modified versions of ssh.c and sshconnect2.c.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 3 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Authentication Abuse An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker. This attack may exploit assumptions made by the target's authentication procedures, such as assumptions regarding trust relationships or assumptions regarding the generation of secret values. This attack differs from Authentication Bypass attacks in that Authentication Abuse allows the attacker to be certified as a valid user through illegitimate means, while Authentication Bypass allows the user to access protected material without ever being certified as an authenticated user. This attack does not rely on prior sessions established by successfully authenticating users, as relied upon for the "Exploitation of Session Variables, Resource IDs and other Trusted Credentials" attack patterns.
- Exploiting Trust in Client (aka Make the Client Invisible) An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
- Utilizing REST's Trust in the System Resource to Register Man in the Middle This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to place man in the middle once SSL is terminated. Rest applications premise is that they leverage existing infrastructure to deliver web services functionality. An example of this is a Rest application that uses HTTP Get methods and receives a HTTP response with an XML document. These Rest style web services are deployed on existing infrastructure such as Apache and IIS web servers with no SOAP stack required. Unfortunately from a security standpoint, there frequently is no interoperable identity security mechanism deployed, so Rest developers often fall back to SSL to deliver security. In large data centers, SSL is typically terminated at the edge of the network - at the firewall, load balancer, or router. Once the SSL is terminated the HTTP request is in the clear (unless developers have hashed or encrypted the values, but this is rare). The attacker can utilize a sniffer such as Wireshark to snapshot the credentials, such as username and password that are passed in the clear once SSL is terminated. Once the attacker gathers these credentials, they can submit requests to the web service provider just as authorized user do. There is not typically an authentication on the client side, beyond what is passed in the request itself so once this is compromised, then this is generally sufficient to compromise the service's authentication scheme.
- Man in the Middle Attack This type of attack targets the communication between two components (typically client and server). The attacker places himself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never intercepted. This interposition is transparent leaving the two compromised components unaware of the potential corruption or leakage of their communications. The potential for Man-in-the-Middle attacks yields an implicit lack of trust in communication or identify between two components.
Exploit-Db
description FreeSSHD 2.1.3 - Remote Authentication Bypass Exploit (0day). CVE-2012-6066. Remote exploit for windows platform id EDB-ID:23080 last seen 2016-02-02 modified 2012-12-02 published 2012-12-02 reporter kingcope source https://www.exploit-db.com/download/23080/ title FreeSSHD 2.1.3 - Remote Authentication Bypass Exploit 0day description Freesshd Authentication Bypass. CVE-2012-6066. Remote exploit for windows platform id EDB-ID:24133 last seen 2016-02-02 modified 2013-01-15 published 2013-01-15 reporter metasploit source https://www.exploit-db.com/download/24133/ title Freesshd Authentication Bypass description FreeFTPD - Remote Authentication Bypass Exploit (0day). CVE-2012-6066. Remote exploit for windows platform id EDB-ID:23079 last seen 2016-02-02 modified 2012-12-02 published 2012-12-02 reporter kingcope source https://www.exploit-db.com/download/23079/ title FreeFTPD - Remote Authentication Bypass Exploit 0day
Metasploit
| description | This module exploits a vulnerability found in FreeSSHd <= 1.2.6 to bypass authentication. You just need the username (which defaults to root). The exploit has been tested with both password and public key authentication. |
| id | MSF:EXPLOIT/WINDOWS/SSH/FREESSHD_AUTHBYPASS |
| last seen | 2020-05-26 |
| modified | 2018-11-17 |
| published | 2013-01-13 |
| references | |
| reporter | Rapid7 |
| source | https://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/windows/ssh/freesshd_authbypass.rb |
| title | Freesshd Authentication Bypass |
Nessus
| NASL family | Gain a shell remotely |
| NASL id | FREEFTPD_SFTP_AUTH_BYPASS.NASL |
| description | The SFTP server included with freeFTPd or freeSSHd has an authentication bypass vulnerability. Authentication can be bypassed by opening an SSH channel before any credentials are provided. A remote, unauthenticated attacker could exploit this to login without providing credentials. After logging in, uploading specially crafted files could result in arbitrary code execution as SYSTEM. Refer to the researcher |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 63223 |
| published | 2012-12-11 |
| reporter | This script is Copyright (C) 2012-2019 and is owned by Tenable, Inc. or an Affiliate thereof. |
| source | https://www.tenable.com/plugins/nessus/63223 |
| title | freeFTPd / freeSSHd SFTP Authentication Bypass |
| code | |
Packetstorm
| data source | https://packetstormsecurity.com/files/download/119546/freesshd_authbypass.rb.txt |
| id | PACKETSTORM:119546 |
| last seen | 2016-12-05 |
| published | 2013-01-15 |
| reporter | metasploit.com |
| source | https://packetstormsecurity.com/files/119546/FreeSSHd-1.2.6-Authentication-Bypass.html |
| title | FreeSSHd 1.2.6 Authentication Bypass |
Seebug
| bulletinFamily | exploit |
| description | BUGTRAQ ID: 56785 CVE(CAN) ID: CVE-2012-6066 freeSSHd是开源的SSH和SFTP服务器。 freeFTPd和其内置SFTP服务器存在身份验证绕过漏洞，在提供证书之前,打开SSH通道可绕过身份验证。未经身份验证的远程攻击者可利用此漏洞登录，而不提供任何证书，登录后，上传特制的文件可以系统权限执行任意代码。 0 freeSSHd 1.2.6 厂商补丁： freeSSHd -------- 目前厂商还没有提供补丁或者升级程序，我们建议使用此软件的用户随时关注厂商的主页以获取最新版本： http://freesshd.com/ |
| id | SSV:60544 |
| last seen | 2017-11-19 |
| modified | 2012-12-26 |
| published | 2012-12-26 |
| reporter | Root |
| source | https://www.seebug.org/vuldb/ssvid-60544 |
| title | FreeSSHd freeSSHd.exe 远程身份验证绕过漏洞 |