Understanding and Selecting SIEM/LM: Advanced Features
We’ve already discussed the basic features of a SIEM/Log Management platform, including collection, aggregation and normalization, correlation and alerting, reporting and forensics, and deployment architectures. But these posts cover the core functions, and are part of what each products in the space will bring to the table. As markets evolve and vendors push to further differentiate themselves, more and more capabilities are integrated into the platforms. In the case of SIEM/LM, this means pumping more data into the analysis engine, and making engine smarter. The idea is to make 1+1 produce 5, as multiple data types provide more insight than a single source – that’s the concept, anyway. To be clear, having more data does not make directly the product any better. The only way to really leverage additional data is to build correlation rules and alerts and reports that utilize the extra data. Let’s take a tour through some of the advanced data types you’ll see integrated into SIEM/LM platforms. Flow Network flow data is the connection records that stream out of a router or switch. These small and simple data files/streams typically list source, destination, and packet type. Flow data was really the first new data type which, when integrated with event and log data, really made the systems smarter. Flow data allowed the system to establish a baseline and scan for anomalous network traffic as the first indication of a problem. An entire sub-market of network management – network behavioral analysis – revolves around analyzing and visualizing flow data to understand the traffic dynamics of networks, and pinpointing performance and capacity issues before they impact users. Many of the NBA vendors have been unsuccessfully trying to position their products in the security market; but in combination with events and logs, flow data is very useful. As an example, consider a typical attack where a web server is compromised and then used as a pivot to further compromise an application server and the backend database server. The data needs to be exfiltrated in some way, so the attackers establish a secure pipe to an external zombie device. But the application server doesn’t typically send data to an external device, so flow data would show an anomalous traffic flow. At that point an administrator could analyze the logs, with correlated activity showing a new account created on the database server, and identifying the breach. Could an accurate correlation rule have caught the reconnaissance and subsequent compromise of the servers? Maybe. But the network doesn’t lie, and at some point the attackers need to move the data. These types of strange network flows can be a great indicator of a successful attack, but remember strange flows only appear after the attack has occurred. So flow data is really for reacting faster to attacks already underway. Even more powerful is the ability to set up compound correlation rules, which factor in specific events and flow scenarios. Of course setting up these rules is complicated and they require a lot of tuning, but once the additional data stream is in place, there are many options for how to leverage it. Identity Everyone wants to feel like more than just a number, but when talking about SIEM/Log Management, your IP address is pretty much who you are. You can detect many problems by just analyzing all traffic indiscriminately, but this tends to generate plenty of false positives. What about the scenario where the privileged user makes a change on a key server? Maybe they used a different device, which had a different IP address. This would show up as an unusual address for that action, and could trigger an alert. But if the system were able to leverage identity information to know the same privileged user was making the change, all would be well, right? That’s the idea behind identity integration with SIEM/LM. Basically, the analysis engine pulls in directory information from the major directory stores (Active Directory & LDAP) to understand who is in the environment and what groups they belong to, which indicates what access rights they have. Other identity data – such as provisioning and authentication information – can be pulled in to enable advanced analysis, perhaps pinpointing a departed user accessing a key system. The holy grail of identity integration is user activity monitoring. Yup, Big Brother lives – and he always knows exactly what you are doing. In this scenario you’d be able to set up a baseline for a group of users (such as Accounting Clerks), including which systems they access, who they communicate with, and what they do. There are actually a handful of other attributes that help identify a single user even when using generic service accounts. Then you can look for anomalies, such as an accounting clerk accessing the HR system, making a change on a sensitive server, or even sending data to his/her Gmail account. This isn’t a smoking gun, per se, but it does give administrators a place to look for issues. Again, additional data types beyond plain event logs can effectively make the system smarter and streamline problem identification. Database Activity Monitoring Recently SIEM/LM platforms have been integrating Database Activity Monitoring (DAM), which collects very detailed information about what is happening to critical data stores. As with the flow data discussed above, DAM can serve up activity and audit data for SIEM. These sources not only provide more data, but add additional context for analysis, helping with both correlation and forensic analysis. Securosis has published plenty of information on DAM, which you can check out in our research library. The purpose of DAM integration is to drive analysis deeper into database transactions, gaining the ability to detect patterns which indicate successful compromise or misuse. As a simple example, if a mobile user gets infected at Starbucks (like that ever happens!) and then unwittingly provides access to the corporate network, the attacker then proceeds to compromise the database. The DAM device monitors the transactions to and from the database, and should see