A security agent implemented on a computing device is described herein. The security agent is configured to detect file-modifying malware by detecting that a process is traversing a directory of the memory of the computing device and detecting that the process is accessing files in the memory according to specified file access patterns. The security agent can also be configured to correlate actions of multiple processes that correspond to a specified file access pattern and detect that one or more of the multiple processes are malware by correlating their behavior.