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###################################################################### # Exploit Title: Samba.org and OpenLDAP.org Reflected XSS # Date: 02/04/2015 # Author: Yann CAM @ Synetis - ASafety # Vendor or Software Link: www.samba.org & www.openldap.org # Version: / # Category: Reflected Cross Site Scripting # Google dork: # Tested on: Samba.org and OpenLDAP.org main domains ###################################################################### Samba description : ====================================================================== Samba is a free software re-implementation of the SMB/CIFS networking protocol, and was originally developed by Andrew Tridgell. Samba provides file and print services for various Windows clients and can integrate with a Windows Server domain, either as a Domain Controller (DC) or as a domain member. As of version 4, it supports Active Directory and Windows NT domains. www.samba.org is the main domain of the project. OpenLDAP description : ====================================================================== OpenLDAP is a free, open source implementation of the Lightweight Directory Access Protocol (LDAP) developed by the OpenLDAP Project. It is released under its own BSD-style license called the OpenLDAP Public License. www.openldap.org is the main domain of the project. JitterBug project description : ====================================================================== JitterBug is a web based bug tracking system. It was originally developed by the Andrew Tridgell to handle bug tracking, problem reports and queries from Samba users. It is now available under the GNU General Public License in the hope that it will be useful for other projects. JitterBug operates by receiving bug reports via email or a web form. Authenticated users can then reply to the message, move it between different categories or add notes to it. In some ways JitterBug is like a communal web based email system. This web page is itself a JitterBug page. You can get an idea of what JitterBug can do by playing with the various links and buttons. JitterBug was used by many others open-source projects like Gnome, rsync, The Gimp, linux-patches, ProFTPD, Willows, Java Linux, WindowMaker, mod_ssl, GnuCash or OpenLdap. Only OpenLDAP and Samba use it currently, so they are both impacted by the vulnerability describes here. RXSS Vulnerability description - PoC : ====================================================================== A reflected XSS is available in the JitterBug bug tracking project provided on the samba.org and openldap.org websites. Through this vulnerability, an attacker could tamper with page rendering, redirect victims to fake Samba/OpenLDAP portals, or capture Samba's (OpenLDAP) users credentials such cookies. It's also possible to forge a fake page with this XSS to provide a backdoored version of softwares to users. This reflected XSS is on GET "id" variable and is not properly sanitized before being used to his page. Tested on Firefox 35.0. PoC: http://www.samba.org/cgi-bin/jitterbug/CVS?id=1337</TITLE><img src=x onerror="alert(/Reflected XSS - Yann CAM @asafety/)" /><TITLE>;selectid=1337 JitterBug future : ====================================================================== As indicated by Samba : The JitterBug project is no longer being actively maintained. Jitterbug has known unfixed security vulnerabilities. Unless you know exactly what you are doing, you should not use it any more. If you wish to take over as the maintainer then please contact Andrew Tridgell at [email]jitterbug@tridgell.net[/email] A possible patch is to sanitize each call of the jitterbug.c file : void print_title(char *fmt, ...) Which injects GET vars directly in HTML source generated : print_title('%s - %s/%s', lp_title(), directory, cgi_variable('id')); In the cgi.c file, there is a potential function to escape all dangerous chars : char *urlquote(char *s) Screenshots : ====================================================================== - [url]http://www.asafety.fr/data/20141126-RXSS_openldap.org_synetis_001.png[/url] - [url]http://www.asafety.fr/data/20141126-RXSS_openldap.org_synetis_002.png[/url] - [url]http://www.asafety.fr/data/20141126-RXSS_samba.org_synetis_001.png[/url] - [url]http://www.asafety.fr/data/20141126-RXSS_samba.org_synetis_002.png[/url] Solution: ====================================================================== Fixed by OpenLDAP team (no details) JitterBug is no longer maintained on Samba website. Thanks to both team, Samba and OpenLDAP, for their kindness and responsiveness. Additional resources : ====================================================================== - [url]https://www.samba.org/jitterbug/[/url] - [url]http://www.openldap.org/its/index.cgi/Web?id=7988[/url] - [url]https://bugzilla.samba.org/show_bug.cgi?id=10967[/url] - [url]http://www.asafety.fr/vuln-exploit-poc/contribution-reflected-xss-vulnerabilites-dans-samba-org-et-openldap-org[/url] - [url]http://www.synetis.com[/url] Report timeline : ====================================================================== 2014-11-26 : Samba ticket created to alert team with details and PoC. 2014-11-26 : OpenLDAP ticket created to alert team with details and PoC. 2014-11-26 : OpenLDAP fix the vulnerability. 2014-11-27 : Samba response with additional questions. 2015-03-30 : New comment to get a status 2015-03-30 : JitterBug on Samba.org website is disabled and the project is no more longer maintained. 2015-04-02 : Public advisory Credits : ====================================================================== 88888888 88 888 88 88 888 88 88 788 Z88 88 88.888888 8888888 888888 88 8888888. 888888. 88 88 888 Z88 88 88 88 88 88 88 8888888 88 88 88 88 88 88 88 88 888 888 88 88 88 88 88888888888 88 88 888888 88 88 88 8. 88 88 88 88 88 888 888 ,88 8I88 88 88 88 88 88 88 .88 .88 ?8888888888. 888 88 88 88888888 8888 88 =88888888 888. 88 88 [url]www.synetis.com[/url] 8888 Consulting firm in management and information security Yann CAM - Security Consultant @ Synetis | ASafety -- SYNETIS | ASafety CONTACT: [url]www.synetis.com[/url] | [url]www.asafety.fr[/url] Source

Samba Remote Code Execution Vulnerability – CVE-2015-0240 The Samba team reported CVE-2015-0240 last February 23, 2015. This vulnerability is very difficult to exploit and we are not aware of successful exploitation. However, it is quite interesting from the point for view of detection. There are two important facts: The vulnerability resides in the Netlogon Remote Protocol implementation of Samba which is a very high-level application protocol that can be used over different transports configurations. To execute the vulnerable code the attacker doesn’t need be authenticated and can use many ways to launch the attacks because of the previous point. This is very motivating for attackers as they can find ways to bypass Intrusion Prevention System (IPS). There is a very good public description about the vulnerability, which can be found at this link. In this post, we will discuss it from the point of view of involved protocols and possible attack surfaces. Vulnerability description The vulnerability resides in the Netlogon Remote Protocol implementation of Samba, specifically in the method NetrServerPasswordSet. The Netlogon Remote Protocol was implemented for interoperability with Microsoft Windows environments and for simulating Primary Domain Controllers. Using the Netlogon Remote Protocol Windows and Linux machines can be part of the Samba PDC domain even without the use of Active Directory. The method NetrServerPasswordSet is used to change the machine account password in a Samba domain. The method NetrServerPasswordSet is implemented in _netr_ServerPasswordSet() in the source file samba\source3\rpc_server\netlogon\srv_netlog_nt.c. The “creds” pointer is passed into netr_creds_server_step_check() without initialization. The following figure shows the vulnerable code section: Figure 1. Vulnerable code section The triggering conditions can be different for Samba v3 and Samba v4 as pointed in this analysis. The attacker can control “computer_name” and “credentials” to reach the vulnerable code section making this vulnerability as possibly exploitable. There is a public POC triggering the vulnerable code. Running this POC and doing dynamic analysis shows that effectively the method _netr_ServerPasswordSet is called. The following figure shows the resumed call graph of Samba. Figure 2. Call graph of Samba Running Samba with high level debugging can allow us to get more runtime information. Example of a command: smbd –D –S /etc/samba/smb.conf -d 10 The following figure shows a section of the resulting log after running the POC. After some more lines we got: This error message is logged by the function schannel_fetch_session_key_tdb and returns the error with NT_STATUS_OBJECT_NAME_NOT_FOUND. This function is called by shannel_check_creds_state. Figure 4. The error NT_STATUS_OBJECT_NAME_NOT_FOUND The error NT_STATUS_OBJECT_NAME_NOT_FOUND will force _netr_ServerPasswordSet to free the “creds” pointer. Looking at the network packets in the following figure we can see the Netlogon Protocol using the transport RPC over SMB. Figure 5. Netlogon Protocol using the transport RPC over SMB And this is one important point regarding to the attack detection. The Netlogon protocol is a high-level application protocol and can use two transport types: RPC over SMB and RPC over TCP/IP. The next section discusses more about this topic. Attack Delivery Mechanisms The Netlogon Remote Protocol is a very high level application protocol that can run on different protocol stack configurations. The following figure shows it. Figure 6. Netlogon Protocol runs on different protocol stack configurations Figure 6 shows that theoretically, an attacker can use two stack configurations to reach the vulnerable code. They are: RPC over TCP/IP and RPC over SMB. These two configurations will use different network ports and communication mechanisms. This is a panacea for implementing attacks bypassing IPS. But even more interesting is the case over SMB where the NetrServerPasswordSet can be called using several SMB commands and at the same time the parameters to the method can be encrypted and unencrypted. The following figure shows other ways to call NetrServerPasswordSet. Figure 7. Other ways to call NetrServerPasswordSet Conclusion The vulnerability it is not easy to exploit and we are not aware of public exploits until now. However, the attack can be implemented in many different ways and the fact that it is not required to be authenticated makes it easy for the attackers. Implementing the protection requires coverage of multiple protocol stack configurations and multi commands over SMB. Sursa: Samba Remote Code Execution Vulnerability – CVE-2015-0240