A zero-day flaw allows to run arbitrary commands on macOS systems

Security researchers disclosed a new zero-day flaw in Apple’s macOS Finder that can allow attackers to run arbitrary commands on Macs.

Independent security researcher Park Minchan disclosed a zero-day vulnerability in Apple’s macOS Finder that can be exploited by attackers to run arbitrary commands on Mac systems running any macOS version.

The flaw is due to the way macOS handles inetloc files that causes it to run commands embedded inside. According to the SSD Secure Disclosure advisory, the commands it runs can be local to the macOS allowing the execution of arbitrary commands by the user without any prompts.

An Internet location file is a sort of system bookmark, upon double-clicking one, an online resource or local files (file://) will be opened.

Initially, the flaw was silently addressed by Apple, but Minchan noticed that the IT giant only partially addressed the flaw. However, the expert discovered that it is still possible to exploit the flaw using a different protocol, from file:// to FiLe://, to execute the embedded commands.

“A vulnerability in the way macOS processes inetloc files causes it to run commands embedded inside, the commands it runs can be local to the macOS allowing the execution of arbitrary commands by the user without any warning / prompts.” reads the SSD Secure Disclosure advisory. “Newer versions of macOS (from Big Sur) have blocked the file:// prefix (in the com.apple.generic-internet-location) however they did a case matching causing File:// or fIle:// to bypass the check.”

The researcher also PoC exploit code for this issue and a video demo:

According to BleepingComputer, at the time of this writing, the PoC code has a detection rate of zero VirusTotal.

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Pierluigi Paganini

(SecurityAffairs – hacking, zero-day)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.