Cutting through the noise of false positives: Time to take back control

The recent mega-breach experienced by US retail brand Target was devastating to the company and its customers

The recent mega-breach experienced by US retail brand Target was devastating to the company and its customers. Executives, including the CIO and the CEO, got the sack because of it. The amazing part of this story was that Target’s security systems actually alerted IT staff to the offending attack in plenty of time to stop it, but it got through anyway.

Some may speculate that the Target security team didn’t do its job, but the truth is likely far more complicated. Highly-sophisticated and sensitive security detection and monitoring tools send alerts frequently, and when all the tools being used by an enterprise the size of Target are added up, you’re left with a “boy who cried wolf” scenario in which hundreds of alerts are going off simultaneously. This makes deciphering the real threats a tall task indeed.

Given the multi-layer “defence-in-depth” approach commonly applied to IT security, it is rational that organisations seek to automate as much of their security posture as possible in an attempt to reduce complexity and security operations workloads.

However, whilst automating the detection of vulnerabilities, threats and attacks is great when it works accurately, what is less helpful is the time lost chasing down security events that are unexpected but not nefarious network, user or system behaviours.

As no automated system is 100 percent accurate in blocking or alerting, we’re left with some amount of inaccurate and potentially time-consuming alerts that have to be handled. More specifically, we’re talking about false positives.

False positives are:

• A waste of organisational resources (time, money, manpower)

• A fact of life for the foreseeable future with current automated alerting (IDS)/blocking (IPS) technologies

• Better than false negatives, which can lull you into complacency and risk exposure

Heuristics, professional instinct and contextual understanding all make useful contributions to the understanding and decision making associated with managing resolution of false positives.

They provide mental “shortcuts” to forming understanding, but also introduce cognitive biases that frame and anchor perceptions and ultimately influence our decision-making.

When faced with a security alert, Security Operations (SecOps) professionals are under pressure to swiftly analyse the situation, build an understanding, formulate options and take appropriate action to achieve resolution. They’re also often under pressure from their organisation’s senior leadership to provide explanations and answers.

However, there are often complexities and criticalities associated with security alerts that can’t quickly be understood without a robust understanding of context, actual network traffic and content. As such, SecOps pros are often left to make an estimate on what caused the alert and the appropriate response to take.

A recent study* uncovered that 87% of Network and Security operations teams had to report the root cause of a network or security issue without all the information required to be 100% accurate, and that 77% of them incorrectly reported the root cause of the issue to their senior management.

So, how can SecOps pros give themselves the best chance of technical and organisational success by ensuring that their actions are informed, appropriate and effective?

It is here that the irrefutable evidence and insight that can be derived from the capture and examination of network traffic before, during, and after the alert of interest provides the clarity and understanding needed to quickly resolve the issue or, if appropriate, choose to ignore the alert.

Approaches to capture, index, search and recall captured traffic can vary in cost and complexity, ranging from simple open source software tools run in a PC and used in a reactive manner, up to always-on high performance, high fidelity Intelligent Network Recording solutions capable of operating at sustained link bandwidths up to 100Gb per second (Gbps).

In the case of intelligent network recorders and distributed recording fabrics, it’s also possible (and so desirable) to integrate these directly into the SecOps Alerting and Analysis tools. Such integration dramatically reduces the investigation and analysis timescale and reduces the chance of introducing operator errors by enabling a “click to packets of interest” from within their existing tools that provide rapid access, and optimising analytic task workflows between analysts.

Automated detection and alerting of potential network based threats all continue to have extremely constructive roles to play in enterprise security architecture.

However, without the evidence of exactly what has traversed the network, where and when, and right down to the make-up of each and every single packet SecOps teams are denied a truly pervasive and entirely accurate picture of what’s occurring.

Integration of network packet capture into detection and alerting tools enables SecOps to derive actionable insight and certainty of what’s occurred by using network packet inspection and visualization techniques.

When SecOps are being swamped with security alerts, compounded with the associated demands from above for answers and actions, the peace of mind from knowing they’ve accurately identified and understood the salient issues at play - and knowing exactly how to deal with them - will be invaluable.

* Emulex 2014 Visibility Study

Matt Walmsley is senior marketing manager, EMEA, Endace Division of Emulex

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