Adam Caudill

Security Engineer, Researcher, & Developer

  • TLS Certificates from the Top Million Sites

    Thanks to the recent WoSign / StartCom issues with misused or flawed certificates, there was a question about how many of the certificates issued were actually active – so this seemed to be a good time to run a scan against the Alexa top 1 million sites to see what I could find. Scan information: The scan was ran with an 8 second timeout – so any server that couldn’t complete a handshake within 8 seconds isn’t counted.

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  • Ruby + GCM Nonce Reuse: When your language sets you up to fail…

    A couple hours ago, Mike Santillana posted to oss-security about a rather interesting find in Ruby’s OpenSSL library; in this case, the flaw is subtle – so much so that it’s unlikely that anyone would notice it, and it’s a matter of a seemingly insignificant choice that determines if your code is affected. When performing AES-GCM encryption, if you set the key first, then the IV, and you are fine – set the IV first, you’re in trouble.

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  • Testing for SWEET32 with YAWAST

    Testing for SWEET32 isn’t simple – when the vulnerability was announced, some argued that the best solution was to assume that if a TLS server supported any of the 3DES cipher suites, consider it vulnerable. The problem is, it’s not that simple. On my employer’s corporate blog, I wrote about practical advice for dealing with SWEET32 – and pointed out that there are ways around the vulnerability, and some are quite simple.

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  • Developers: Placing Trust in Strangers

    Much has been said, especially recently, about that mess of dependencies that modern applications have – and for those of us working in application security, there is good reason to be concerned about how these dependencies are being handled. While working on YAWAST, I was adding a new feature, and as a result, I needed a new dependency – ssllabs.rb. While most Ruby dependencies are delivered via Gems, ssllabs.rb is a little different – it pulls directly from Github:

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  • Threat Modeling for Applications

    Whether you are running a bug bounty, or just want a useful way to classify the severity of security issues, it’s important to have a threat-model for your application. There are many different types of attackers, with different capabilities. If you haven’t defined the attackers you are concerned about, and how you deal with them – you can’t accurately define just how critical an issue is. There are many different views on threat models; I’m going to talk about a simple form that’s quick and easy to define.

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  • When Hashing isn’t Hashing

    Anyone working in application security has found themselves saying something like this a thousand times: “always hash passwords with a secure password hashing function.” I’ve said this phrase at nearly all of the developer events I’ve spoken at, it’s become a mantra of sorts for many of us that try to improve the security of applications. We tell developers to hash passwords, then we have to qualify it to explain that it isn’t normal hashing.

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  • Seamless Phishing

    Phishing attacks are a fact of life, especially for users of the largest sites – Facebook being the most common I’m seeing today. Pretty much everybody, from the SEC to antivirus companies have published guides on what users should do to avoid phishing – so I picked one at random and pulled out the key points: 1). Always check the link, which you are going to open. If it has some spelling issues, take a double-take to be sure — fraudsters can try to push on a fake page to you.

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  • PL/SQL Developer: HTTP to Command Execution

    While looking into PL/SQL Developer – a very popular tool for working with Oracle databases, to see how it encrypts passwords I noticed something interesting. When testing Windows applications, I make it a habit to have Fiddler running, to see if there is any interesting traffic – and in this case, there certainly was. PL/SQL Developer has an update mechanism which retrieves a file containing information about available updates to PL/SQL Developer and other components; this file is retrieved via HTTP, meaning that an attacker in a privileged network position could modify this file.

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  • Crypto Crisis: Fear over Freedom

    Yesterday, President Obama spoke at SXSW on topics including the oft-discussed fight between Apple and the FBI – what he called for, while more thoughtful than some of the other comments that we have been hearing from Washington, was still tragically misinformed. He repeated the call for a compromise, and by compromise, he meant backdoors. Here, I feel I must paraphrase one of my favorite authors to properly express the magnitude of what’s being discussed here:

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  • PL/SQL Developer: Nonexistent Encryption

    (See here for another issue discovered during this research; Updates over HTTP & Command Execution.) PL/SQL Developer by Allround Automations has an option to store the user’s logon history with passwords – the passwords are encrypted with a proprietary algorithm. At this point, you should know how this is going to go. For those that don’t know, PL/SQL Developer is a tool for developers and database administrators to access Oracle – an essential tool in many enterprise environments.

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