Research

Mike Bailey highlights a key problem with web applications in his post on diversity. Having dealt with these issues as a web developer (a long time ago), I want to add a little color. We tend to talk about diversity as being good, usually with biological models and discussions of monoculture. I think Dan Geer was the first to call out the dangers of using only a single computing platform, since one exploit then has the capability of taking down your entire organization. But the heterogeneous/homogenous tradeoffs aren’t so simple. Diversity reduces the risk of a catastrophic single point of failure by increasing the attack surface and potential points of failure. Limited diversity is good for something like desktop operating systems. A little platform diversity can keep you running when something very bad hits the primary platform and takes those systems down. The trade off is that you now have multiple profiles to protect, with a great number of total potential vulnerabilities. For example, the Air Force standardized their Windows platforms to reduce patching costs and time. What we need, on the OS side, is limited diversity. A few standard platform profiles that strike the balance between reducing the risk that a single problem will take us completely down, while maintaining manageability through standardization. But back to Mike’s post and web applications… With web applications what we mostly see is false diversity. The application itself is a monolithic entity, but use of multiple frameworks and components only increases the potential attack surface. With desktop operating systems, diversity means a hole in one won’t take them all down. With web applications, use of multiple languages/frameworks and even platforms increases the number of potential vulnerabilities, since exploitation of any one of those components can generally take down/expose the entire application. When I used to develop apps, like every web developer at the time, I would often use a hodgepodge of different languages, components, widgets, etc. Security wasn’t the same problem then it is now, but early on I learned that the more different things I used, the harder it was to maintain my app over time. So I tended towards standardization as much as possible. We’re doing the same thing with our sooper sekret project here at Securosis – sticking to as few base components as we can, which we will then secure as well as we can. What Mike really brings to the table is the concept of how to create real diversity within web applications, as opposed to false diversity. Read his post, which includes things like centralized security services and application boundaries. Since with web applications we don’t control the presentation layer (the web browser, which is a ‘standard’ client designed to accept input from nearly anything out there), new and interesting boundary issues are introduced – like XSS and CSRF. Adrian and I talk about this when we advise clients to separate out encryption from both the application and the database, or use tokenization. Those architectures increase diversity and boundaries, but that’s very different than using 8 languages and widgets to build your web app. Share:

Thanks to Aza Raskin, this week we learned of a new phishing attack, dubbed “tabnabbing” by Brian Krebs. It opening a tab (unbeknownst to the user), changes the favicon, and does a great job of impersonating a web page – or a bank account, or any other phishing target. Through the magic of JavaScript, the tabs can be controlled and the attack made very hard to detect since it preys on the familiarity of users with common webmail and banking interfaces. So what do you do? You can run NoScript in your Firefox browser and to prevent the JavaScript from running (unless you idiotically allowed JavaScript on a compromised page). Another option is leveraging a password manager. Both Rich and I have professed our love for 1Password on the Mac. 1Password puts a button in your browser, and when logging in brings up a choice of credentials for that specific domain to automatically fill in the form. So when I go to Gmail, logging in is as easy as choosing one of the 4 separate logins I use on google.com domains. Now if I navigate to the phishing site, which looks exactly like Gmail, I’d still be protected. 1Password would not show me any stored logins for that domain, since presumably the phisher must use a different domain. This isn’t foolproof because the phisher could compromise the main domain, host the page there, and then I’m hosed. I could also manually open up 1Password and copy/paste the login credentials, but that’s pretty unlikely. I’d instantly know something was funky if my logins were not accessible, and I’d investigate. Both of these scenarios are edge cases and I believe in a majority of situations I’d be protected. I’m not familiar with password managers on Windows, but if they have similar capabilities, we highly recommend you use one. So not only can I use an extremely long password on each sensitive site, I get some phishing protection as a bonus. Nice. Share:

The first four posts our the SIEM series dealt with understanding what SIEM is, and what problems it solves. Now we move into how to select the right product/solution/service for your organization, and that involves digging into the technology behind SIEM and log management platforms. We start with the foundation of every SIEM and Log Management platform: data collection. This is where we collect data from the dozens of different types of devices and applications we monitor. ‘Data’ has a pretty broad meaning – here it typically refers to event and log records but can also include flow records, configuration data, SQL queries, and any other type of standard data we want to pump into the platform for analysis. It may sound easy, but being able to gather data from every hardware and software vendor on the planet in a scalable and reliable fashion is incredibly difficult. With over 20 vendors in the Log Management and SIEM space, and each vendor using different terms to differentiate their products, it gets very confusing. In this series we will define vendor-neutral terms to describe the technical underpinnings and components of log data collection, to level-set what you really need to worry about. In fact, while log files are what is commonly collected, we will use the term “data collection”, as we recommend gathering more than just log files. Data Collection Overview Conceptually, data collection is very simple: we just gather the events from different devices and applications on our network to understand what is going on. Each device generates an event each time something happens, and collects the events into a single repository known as a log file (although it could actually be a database). There are only four components to discuss for data collection, and each one provides a pretty straight-forward function. Here are the functional components: Fig 1. Agent data collector Fig 2. Direct connections to the device Fig 3. Log file collection Source: There are many different sources – including applications, operating systems, firewalls, routers & switches, intrusion detection systems, access control software, and virtual machines – that generate data. We can even collect network traffic, either directly from the network for from routers that support Netflow-style feeds. Data: This is the artifact telling us what actually happened. The data could be an event, which is nothing more than a finite number of data elements to describe what happened. For example, this might record someone logging into the system or a service failure. Minimum event data includes the network address, port number, device/host name, service type, operation being performed, result of the operation (success or error code), user who performed the operation, and timestamp. Or the data might just be configuration information or device status. In practice, event logs are pretty consistent across different sources – they all provide this basic information. But each offers additional data, including context. Additional data types may include things such as NetFlow records and configuration files. In practice, most of the data gathered will be events and logs, but we don’t want to arbitrarily restrict our scope. Collector: This connects to a source device, directly or indirectly, to collect the events. Collectors take different forms: they can be agents residing on the source device (Fig. 1), remote code communicating over the network directly with the device (Fig. 2), an agent writing code writing to a dedicated log repository (Fig. 3), or receivers accepting a log file stream. A collector may be provided by the SIEM vendor or a third party (normally the vendor of the device being monitored). Further, the collector functions differently, depending upon the idiosyncrasies of the device. In most cases the source need only be configured once, and events will be pushed directly to the collector or into a neutral log file read by it. In some cases, the collector must continually request data be sent, polling the source at regular intervals. Protocol: This is how collector communicates with the source. This is an oversimplification, of course, but think of it as a language or dialect the two agree upon for communicating events. Unfortunately there are lots of them! Sometimes the collector uses an API to communicate directly with the source (e.g., OPSEC LEA APIs, MS WMI, RPC, or SDEE). Sometimes events are streamed over networking protocols such as SNMP, Netflow, or IPFIX. Sometimes the source drops events into a common file/record format, such as syslog, Windows Event Log, or syslog-ng, which is then read by the collector. Additionally, third party applications such as Lasso and Snare provide these features as a service. Data collection is conceptually simple, but the thousands of potential variations makes implementation a complex mess. It resembles a United Nations meeting: you have a whole bunch of people talking in different languages, each with a particular agenda of items they feel are important, and different ways they want to communicate information. Some are loquacious and won’t shut up, while others need to be poked and prodded just to extract the simplest information. In a nutshell, it’s up to the SIEM and Log Management platforms to act as the interpreters, gathering the information and putting it into some useful form. Tradeoffs Each model for data collection has trade-offs. Agents can be a powerful proxy, allowing the SIEM platform to use robust (sometimes proprietary) connection protocols to safely and reliably move information off devices; in this scenario device setup and configuration is handled during agent installation. Agents can also take full advantage of native device features, and can tune and filter the event stream. But agents have fallen out of favor somewhat. SIEM installations cover thousands of devices, which means agents can be a maintenance nightmare, requiring considerable time to install and maintain. Further, agents’ processing and data storage requirements on the device can affect stability and performance. Finally, most agents require administrative access, which creates am additional security concern on each device. Another common technique streams events to log files, such as syslog or the Windows Event