defence in depth.

The other day I noticed a strange response I hadn't seen before when running a VERSION command against an 11.1.0.7 Listener: It seemed as though the Listener was leaking memory. I was able to reproduce this issue across other nodes in the RACs I had access to. Instead of the standard 348 byte TNS VERSION response I was getting a 2011 byte TNS response: I was also able to reproduce the result by running the VERSION command locally using the lsnrctl utility. With a bit of digging it seems as though 11.1.0.7 Listeners with CPU April 2012 (patchset 13621679) are vulnerable to a memory leak issue. Most likely due to a buffer not being terminated/copied correctly. This flaw could potentially come in handy during a pentest when trying to enumerate SIDs/Service names: I was unable to reproduce this flaw on Listeners patched with CPU July 2012 (patchset  13923474) -- meaning Oracle are most likely wise to the issue... Note: I was able to notice...

In recent years, phishing has become an increasingly profitable attack vector for online scammers. According to RSA’s The Year in Phishing (2013) report, the total number of phishing attacks in 2012 increased by 59% and resulted in global losses of $USD 1.5 billion. With this upward trend in online fraud predicted to continue, it’s pertinent to take a look at how these attacks are so successful and what can be done to buck the increasing trend of online fraud. Phishing is the process whereby someone (malicious) masquerades as a trusted entity to solicit information. Relying on the art of deception, these attacks fair particularly well online as people are less likely to pick up on the fraud cues. Phishers frequently target email as their preferred attack medium due to its lack of security controls – in particular, the absence of authentication. The critical issue surrounding email is trust. That is, how can we trust an email has come from who it purports to come from? If we look at...

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...