defence in depth.

Last week I read a post on Brian Krebs’ blog where security researcher Thomas Ptacek was interviewed about his thoughts on the current landscape of password hashing. I found Thomas’ insights into this topic quite pertinent and would like to reiterate his sentiments by talking a little about the importance of choosing the right password hashing scheme. The idea of storing passwords in a “secret” form (as opposed to plain-text) is no new notion. In 1976 the Unix operating system would store password hash representations using the crypt one-way cryptographic hashing function.  As one can imagine, the processing power back then was significantly less than that of current day standards. With crypt only being able to hash fewer than 4 passwords per second on 1976 hardware, the designers of the Unix operating system decided there was no need to protect the password file as any attack would, by enlarge, be computationally infeasible. Whilst this assertion was certainly true in 197...

A common recommendation I often come across is that Internet-facing systems should not be a part of an active Windows domain. As an exercise of interest, I have decided to look at this topic a little deeper and explore what advantage (if any) access to a domain member really provides. In this scenario I will demonstrate how to gain privilege within a Windows domain using only the tools available on a default Windows install. I will be working under the assumption that: I have access to a public terminal (or something similar) with up-to-date anti-virus. I do not have administrative access on the host. I do not have access to any third-party tools. Once connected to a Windows workstation, the first piece of information I want to find is the domain namespace. This can be done a couple of different ways: nbtstat –A <IP-Address> net config workstation Next, because I am working from a domain member, I can query the domain controller and check whether it’s aware of ...

UPDATE [2011-10-15]: The issues described in this post have now been resolved by Apple. Users running OS X Lion 10.7.2 or security update 2011-006 are no longer affected by the vulnerabilities detailed below (CVE-2011-3435 and CVE-2011-3436). For further details on this security update please see Apple's advisory . In 2009 I posted an article on Cracking Mac OS X passwords . Whilst this post has been quite popular, it was written for OS X 10.6 and prior. Since the release of Mac OS X Lion (10.7) in July, I have received numerous requests for an update. Typically, I would have just updated the existing article without the need for a new post. However, during my research I discovered something interesting about OS X Lion that I'd like to share. In previous versions of OS X (10.6, 10.5, 10.4) the process to extract user password hashes has been the same: obtain the user's GeneratedUID and then use that ID to extract hashes from a specific user's shadow file (See my pr...

In Part 1 of the “LM/NTLMv1 Challenge/Response Authentication” series I discussed how both the LANMAN/NTLMv1 protocols operate and the weaknesses that plague these protocols. In this post I will demonstrate how attackers leverage these weaknesses to exploit the LANMAN/NTLMv1 protocols in order to compromise user credentials. For the remainder of this article I will be focusing on attacking the SMB protocol (Windows file sharing) as this is where LANMAN/NTLMv1 is most commonly used. Capturing the Response In order to capture a client’s LANMAN/NTLMv1 response, attackers will often utilise one of two methods: Force the client host to connect to them Conduct a man-in-the-middle (MITM) attack and “sniff” the client’s response To demonstrate these methods, I will be using the Metasploit Framework or Cain and Abel respectively. Metasploit In order for a client host to connect to us, we first need to create a listening SMB service that will accept incoming connections. Fo...

The Microsoft Windows platform uses a myriad of protocols to authenticate users across a network. Two such protocols widely in use today are the LANMAN challenge/response and NTLMv1 protocols. Whilst newer, more secure protocols (such as NTLMv2) are ready to take their place, LANMAN challenge/response and NTLMv1 are still widely deployed today for reasons of interoperability. As with most things Microsoft-related, ubiquity often equates to exploitability. In this two part series I will discuss how the LANMAN challenge/response and NTLMv1 protocols operate, how malicious users can take advantage of their shortcomings, and best practice recommendations for securely deploying these protocols. Microsoft Windows supports two primary algorithms for locally authenticating users. These algorithms generate what’s known as an “LM Hash” or an “NT Hash”. Enabled by default in Windows NT, 2000, XP, and Server 2003, the LM Hash has become synonymous with bad hashing practices over the years...

Protected Extensible Authentication Protocol (PEAP) is often regarded as a secure 802.11 wireless authentication protocol. Whilst PEAP has the ability to become a secure protocol it is certainly not without its deficiencies. I thought I would take this opportunity to provide everyone with an overview of the PEAP protocol by examining what it is, how it works, where its shortcomings lie, and how to secure it. Before we dive into the security concerns surrounding PEAP it is important to know there are currently three versions of the PEAP standard. The version I will be referencing throughout the remainder of this post will be PEAPv0. This is the most common deployment of the PEAP standard. PEAP is a widely deployed Extensible Authentication Protocol (EAP) type used to securely authenticate users against 802.11 wireless networks. Developed by Microsoft, Cisco and RSA, PEAP has been made popular through its continued support by the Microsoft Windows platform. PEAP has the ability to su...

Password wordlists and dictionaries are an often imperative resource for any password auditing exercise. I thought I would take this opportunity to consolidate a list of wordlists /dictionaries for ease of access. Please feel free to post any resources I have omitted in the comments below. I will periodically update this post with any new resources I come across. http://ftp.sunet.se/pub/security/too...all/wordlists/ http://www.skullsecurity.org/wiki/index.php/Passwords ftp://ftp.ox.ac.uk/pub/wordlists/ http://gdataonline.com/downloads/GDict/ ftp://ftp.openwall.com/pub/wordlists/ ftp://ftp.cerias.purdue.edu/pub/dict/ http://www.indianz.ch/tools/doc/wordlist.zip http://www.outpost9.com/files/WordLists.html ftp://ftp.openwall.com/pub/wordlists/passwords/ https://www.securinfos.info/wordlists_dictionnaires.php ftp://ftp.ox.ac.uk/pub/wordlists/ http://www.lostpassword.com/f/wl/bigdict.zip http://www.lostpassword.com/f/wl/French.zip http://www.lostpassword.com/f/wl/Spanish...