The company simultaneously reiterated the narrow scope of ShadowHammer, noting that the malware targeted a "very small and specific user group." It's believed to be an Advanced Persistent Threat -- that is, a state-backed assault against organizations rather than everyday users. Other ASUS devices weren't affected, according to a notice.

While the fix is reassuring, it also raises questions as to why the systems weren't locked down earlier. Update tools are prime targets for hackers precisely because they're both trusted and have deep access to the operating system -- tight security is necessary to prevent an intruder from hijacking the process.