Unauthenticated Arbitrary File Access in HFS2

HFS2 version 2.4.0 and earlier contains an unauthenticated arbitrary file access vulnerability that allows unauthenticated attackers to read, write, append, and delete files anywhere the HFS service account has filesystem access outside the shared folder. Attackers can exploit the macro dispatcher's lack of authorization model combined with the path resolver's failure to confine absolute paths to manipulate the template engine and compromise the confidentiality, integrity, and availability of the host.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched 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

HFS2 version 2.4.0 and earlier suffers from a critical unauthenticated arbitrary file access vulnerability (CVSS 10.0) that enables attackers to read, write, append, and delete files anywhere the HFS service account has filesystem permissions—far beyond the intended shared folder boundaries. The root cause lies in a missing authorization model in the macro dispatcher combined with insufficient path validation in the path resolver, allowing attackers to manipulate absolute paths through the template engine. This vulnerability affects any organization running vulnerable HFS2 versions without authentication barriers, making it particularly dangerous in internet-facing deployments or environments with untrusted network access. The impact spans all three security pillars: confidentiality (unauthorized file reads), integrity (unauthorized file modifications), and availability (file deletion and service disruption).

Casky's 283 matching skills leverage Claude AI's extended reasoning to detect exploitation patterns tied to MITRE techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky would identify suspicious indicators such as unauthorized filesystem enumeration attempts, anomalous template engine requests with path traversal sequences (../ patterns, absolute paths), macro dispatcher calls lacking proper authentication tokens, and lateral file access patterns originating from the HFS service account context. The platform's skill mapping would surface detection opportunities across multiple attack stages—initial reconnaissance probing for HFS instances, exploitation attempts manipulating macro parameters, post-exploitation file exfiltration, and persistence mechanisms via file write/append operations. By correlating these behavioral patterns against the mapped skills, security teams gain visibility into both active exploitation and attack preparation phases.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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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 →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-97360.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-97360

Casky has 283 skills that investigate the attack patterns behind CVE-2026-97360. Run one and get CVSS-scored findings in 3 minutes.

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