What is alert triage in cybersecurity?

Effective triage is much more than responding to yet another alert. Learn how your security team can improve its alert response while saving time and labor.

What is alert triage?

Alert triage in a cybersecurity context refers to the process of receiving alerts, analyzing them for classification and prioritization and then responding appropriately. An efficient, informed triage process is critical to the overall effectiveness of security operations centers (SOC) in many organizations. SOCs may receive thousands of alerts on an average day. Determining which are simply noise and which require investigation is one of the primary workflows supporting cyber defense. Alert triage is a process that, ideally, surfaces the alerts that indicate an active threat (true positives).

The sheer volume of alerts an SOC must handle is just one factor that makes effective alert triage a challenge. Security teams stretched thin by talent shortages and budget constraints are hard-pressed to make judgment calls when alerts lack context or when investigation requires excessive manual effort involving too many tools.

When alert triage is effective, however, SOCs can do more with less, and take a more proactive approach to investigating threats and fine-tuning their detections. Detections based on contextualized evidence are less likely to result in false positives.

Steps in the cybersecurity alert triage process

A SOC’s triage process begins with assigning roles, defining workflows and establishing a process that ensures every alert registers in an established platform, such as system information and event management (SIEM). These are steps to establish and test outside the scope of actually investigating alerts.

Once an alert registers, the SOC’s triage process begins to rely heavily on the quality of data. The process will involve:

• Alert priority assessment. The SIEM, or other platform that registers the alert, is also where an SOC analysts will prioritize it based on what is known about the assets involved in the alert, their value to the organization, a general risk assessment and, if the alert proves to be a true positive, the stage of the attack. A review of device logs and integrated security tools can help the SOC get a general sense of potential blast radius, attack paths and data that may be at risk. Alerts that carry the highest potential risk or involve the most sensitive assets will be prioritized.
• True/false positive assessment. The ideal outcome of this step is for the SOC to make an accurate assessment as quickly as possible, which depends on how much relevant information about the alert the analysts can review with a minimum of effort. They will look for indicators of compromise that might have triggered the alert, or assess what type of behavior is normal for the hosts involved. The analyst may also leverage threat intelligence to determine if the detection is associated with known attack patterns.
  • If the SOC determines the alert is a false positive, it may undertake a review of the alert history and its impact on hosts in the network. They may choose to tune the alert, suppress it for particular IP addresses or disable it if they conclude it’s simply creating noise.
  • If the assessment results in a true positive, the triage process escalates to incident response.
• Incident response/containment. Actions taken at this stage depend on the alert’s severity. Low-severity cases may require simple remediation such as blocking on a firewall. If the SOC suspects the attack is more severe, it may consider whether it must isolate hosts, add new blocking rules, or bring other analysts or decision makers into the response.
• Broadening the investigation. Once the SOC has implemented initial containment steps, it will look for evidence that helps determine the breadth of the attack. It may look for earlier IOCs the security system missed, assess what hosts or networks are compromised or at risk of compromise, where the attack maintains persistence and whether wiping and restoring will be necessary.
• Remediation. The security team will act as quickly as possible to neutralize the threat and take steps to safeguard against a repeat intrusion via patching and/or bolstering security configurations and controls.
• Post-incident analysis. Digital forensics and incident response (DFIR) is a process that often extends beyond alert triage but is an essential part of understanding and processing the preceding steps. The security team may try to determine how the attacker gained access to the system, how long they persisted and the full extent of data that has been compromised or exfiltrated.

How can your SOC improve alert triage?

Alert triage is an often complex process that can be made faster, more accurate, and less resource- intensive through a variety of methods, even when the SOC is staffed with junior analysts still honing their threat detection and response skills. Security solutions that drive many or all of the improvements below can quickly generate a return on investment:

• Retrievable, rich historical context. One of the first questions accompanying an alert will be: Has it been seen before? If the alert is a true positive, what was done to resolve it, and why has the alert reoccurred? If it is a resolved false positive, what tuning, if any, did the alert receive? A triage process that provides quick answers to these questions starts the alert analysis on the right foot.
• Simplified alert descriptions. Incoming alerts benefit when they surface essential information about hosts involved, key technical and connection details, summaries of potential threats and sufficient context for explaining the threat’s implications. AI and LLM technology can also condense the “why” and “what” of alerts by generating summaries of host characteristics and behavior.
• Time sequences. Alerts are enriched not just with analysis of what happened but when it happened. A triage system that synthesizes the content of alerts within a timeline can help analysts understand the rate at which a cyber incident has unfolded and potentially determine patterns within the activity.
• Data synthesis. A system that logs incident timelines, streamlines data access and enriches network metadata can make it easier and faster for analysts to document any findings and make more informed decisions. A process that simplifies data export will also benefit workflows in compliance and forensic analysis. Organizations employing senior analysts may also need advanced displays that enable quick looks into raw alert logs. The SOC will also benefit when packet capture (PCAP) is simplified (in terms of retrieval and storage cost) and given context.
• Bundled IR information. During alert triage, analysts will need to pivot quickly between the alert payload to PCAP and other data sources, and may need to use several tools during the process. Tools that synthesize and/or decode alert payloads and concentrate query results can help analysts at all skill levels execute alert triage more rapidly.

How Corelight improves alert triage

Corelight’s open NDR platform combines a Suricata-based intrusion detection system with the gold standard of network evidence, Zeek^®, entity collections, packet capture and other capabilities to create an analytics solution that can assist SOC analysts at any skill level. Its Guided Triage features are specifically designed to simplify and condense alert data within interactive visual frameworks and make analysis and response faster and more accurate.

Guided Triage is designed to assist the SOC through improved mean time to respond (MTTR) and remediate problems and the high costs associated with storing data and retrieving alert information from a SIEM. Based on detailed knowledge of alert triage challenges and limitations, Guided Triage helps analysts at all skill levels through multiple value-adds, including: