Time-of-Check Time-of-Use in Trend Micro Apex One Signature Verification

A time-of-check time-of-use vulnerability in the Trend Micro Apex One (mac) agent iCore service signature verification could allow a local attacker to escalate privileges on affected installations. Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The following information is provided as informational only for CVE references, as these were addressed already via ActiveUpdate/SaaS updates in mid to late 2025 (SaaS 2507 & 2005 Yearly Release).

Casky was already ahead

This CVE exploits attack patterns that Casky's 203matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2025-71215 is a time-of-check time-of-use (TOCTOU) vulnerability in the Trend Micro Apex One agent's iCore service signature verification mechanism on macOS systems. This weakness allows a local attacker who already has low-privileged code execution to exploit a race condition between when the system checks a signature's validity and when it actually uses that signature, ultimately escalating privileges to a higher level. Organizations running Trend Micro Apex One on macOS endpoints are affected, particularly those that haven't applied the mid-2025 ActiveUpdate/SaaS patches. While the CVSS score of 7 indicates high severity, the vulnerability requires pre-existing local code execution, making it part of a multi-stage attack chain rather than a direct remote compromise vector.

Casky's 203 matching skills use Claude AI with extended reasoning to detect the privilege escalation patterns characteristic of CWE-367 TOCTOU vulnerabilities mapped to MITRE ATT&CK technique TA0004 (Privilege Escalation). Practitioners using Casky would observe findings highlighting suspicious file system operations that occur between verification and usage steps, anomalous process spawning with elevated privileges from low-privileged parent processes, and timing-based anomalies in signature validation workflows. The platform's skills would correlate rapid file modifications targeting signature directories with subsequent elevation attempts, flag race condition indicators like repeated failed signature checks followed by successful exploitation, and identify behavioral signatures of iCore service manipulation. Security teams would see detailed attack flow mappings showing how attackers transition from initial low-privilege code execution to system-level access through signature bypass techniques.

Live Threat IntelligenceComing soon

Casky Risk Score

—

EPSS Probability

—

Shodan Exposure

—

GreyNoise Signal

—

Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

203 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2025-71215.

analyzing-cloud-storage-access-patterns

cloud security · low

Run

analyzing-kubernetes-audit-logs

container security · low

Run

analyzing-office365-audit-logs-for-compromise

cloud security · low

Run

MITRE ATT&CK Techniques

TA0004

Investigate the attack patterns behind CVE-2025-71215

Casky has 203 skills that investigate the attack patterns behind CVE-2025-71215. Run one and get CVSS-scored findings in 3 minutes.

Run the skill that detects this →

X Instagram LinkedIn