Logic drift is the gradual divergence of business rules when the same process is rebuilt in multiple tools, files, or team-owned workflows. Instead of one authoritative rule set, organizations end up with slightly different formulas, approval paths, exception lists, or access checks. Over time, those differences can change results without anyone noticing.
In cyber security, logic drift matters because security and compliance often depend on consistent decisions. If one system blocks a transaction, another may allow it; if one spreadsheet calculates risk differently, incident triage and fraud checks can go wrong. Attackers can abuse these gaps by finding the weakest or least-reviewed version of a process. Defenses focus on reducing duplication and making change visible: central policy management, version control, reusable templates, audit logs, and periodic reconciliation tests. The goal is not just speed, but proving that the same rule still means the same thing everywhere.