A next-generation macOS infostealer is being tracked for targeting cryptocurrency wallets and login credentials on Macs. The threat, tracked under the name Mac.c and linked in reporting to the broader MacSync campaign, is described as a malware-as-a-service tool associated with a developer known as “mentalpositive.” While some reports describe ad-driven distribution, the Hungary-based Nemzeti Kibervédelmi Intézet (NKI) advisory primarily focuses on the malware’s infostealer capabilities rather than providing a confirmed infection count or tying the activity specifically to hijacked Google ads.
How Mac.c Targets Crypto Wallets and Credentials
Mac.c is not a blunt instrument. It is designed with a narrow, high-value target set: cryptocurrency wallets and user authentication data stored on macOS systems. According to a bulletin published by Hungary’s Nemzeti Kibervedelmi Intezet, the malware functions as a next-generation infostealer with a specific focus on extracting sensitive financial and credential data. That focus makes it far more dangerous per infection than a generic adware bundle or browser hijacker, because a single successful compromise can expose wallet data or saved passwords to an attacker.
The malware-as-a-service model means “mentalpositive” does not need to carry out every attack personally. Instead, the developer sells or leases access to the tool, letting other threat actors customize and deploy it against their own targets. This distribution model has fueled rapid adoption among cybercriminals who previously lacked the technical skill to build macOS-specific payloads from scratch. For everyday Mac users, the practical consequence is straightforward: the number of actors capable of deploying this kind of theft tool against them has grown, and the barrier to entry for attackers has dropped sharply.
Ad-Based Delivery Exploits a Trust Gap
Some reporting describes compromised or fraudulent online advertisements as a possible delivery mechanism for MacSync-linked activity, a shift from older macOS threats that often relied on trojanized downloads or phishing. In those scenarios, clicking what appears to be a legitimate sponsored result or display ad can redirect a user to a page that attempts to initiate an installation flow. Because ad supply chains can be abused, users should treat sponsored links with extra caution rather than assuming every ad placement has been fully vetted.
The deeper issue is structural. Apple has spent years marketing macOS as inherently more secure than Windows, and for a long time that reputation was largely earned. But the growth of malware-as-a-service platforms like Mac.c suggests the economics of attacking Macs have shifted. As cryptocurrency adoption has risen and more professionals store high-value credentials on Apple hardware, the incentive for threat actors to invest in macOS-specific tools has increased proportionally. The ad-hijacking vector simply lowers the cost of reaching those users at scale. Without more aggressive ad verification on the platform side and stronger user skepticism toward sponsored links, this delivery channel will likely remain open.
Government Validation and the Mac.c Lineage
What gives the Mac.c threat assessment additional weight is that it is discussed in public-sector cybersecurity materials. Hungary’s NKI/NCSC English-language portal and the NKI advisory describing Mac.c characterize it as an infostealer focused on credential and crypto-related data, and reference research that associates the tool with a developer using the handle “mentalpositive.” These government-linked write-ups help corroborate the malware’s general capabilities and reported lineage, but they should not be read as confirming every distribution detail or any specific infection total on their own.
The broader institutional ecosystem provides additional context. Hungary’s national coordination center supports cyber defense and information sharing, while the country’s interactive threat map visualizes overall attack activity observed across networks. However, these resources are not, by themselves, case counts for a specific malware family. Based on the NKI advisory and related public materials, Mac.c should be treated as a credible macOS infostealer threat, but readers should avoid assuming that government pages confirm a precise number of infections or a specific ad platform as the distribution source unless explicitly stated.
Why Mac Users Can No Longer Rely on Platform Security Alone
For years, the conventional wisdom among casual Mac users was that Apple’s walled-garden approach to software and its Unix-based architecture made macOS a poor target for malware authors. That calculus has changed. The emergence of Mac.c as a commercially available, purpose-built infostealer demonstrates that threat actors now see macOS as a profitable attack surface, not a niche afterthought. The ad-based delivery method compounds the problem because it does not require the user to download a suspicious file from an unfamiliar website. It meets them where they already are: searching the web, clicking on results that look trustworthy, and assuming that Apple’s built-in protections will silently intercept anything dangerous.
Those assumptions overlook how modern attacks actually unfold. Infostealers like Mac.c can be wrapped in seemingly benign installers, abuse legitimate developer certificates, or exploit social engineering to convince users to override macOS security prompts. Even when Apple’s defenses block known binaries, the malware-as-a-service model encourages rapid iteration: as soon as one variant is detected, another can be generated and pushed to affiliates. The Hungarian advisories confirm capabilities and attribution, but they do not claim that platform protections alone are sufficient to contain the threat. In practice, that means Mac users must treat their systems more like high-value enterprise endpoints than consumer appliances and adopt layered defenses that anticipate failure at any single point.
What Comes Next for macOS Threat Defense
The trajectory is clear. As malware-as-a-service platforms lower the barrier for attacking macOS, Apple users need to respond with a mix of technical controls, policy changes, and user education. On the technical side, organizations should treat Mac endpoints as first-class citizens in their security stack: deploy endpoint detection and response tools that understand macOS internals, enforce least-privilege access so that malware cannot freely traverse the system, and monitor for unusual access to browser storage, keychains, and cryptocurrency-related files. Network-level controls that inspect outbound traffic and block connections to known command-and-control infrastructure can also blunt the impact of an infostealer, even if the initial infection succeeds.
At the same time, the ecosystem around macOS needs to adapt. Advertising platforms must tighten verification of sponsored content to reduce the window in which poisoned ads can reach users, and security teams should incorporate threat intelligence from national bodies like Hungary’s cyber agencies into their own detection logic. For individual users, the most effective countermeasures remain behavioral: avoid installing software reached through ads or search-sponsored links, prefer direct navigation to trusted vendors, keep macOS and browsers fully patched, and store cryptocurrency in hardware wallets or segregated environments where possible. The official recognition of Mac.c by government cybersecurity institutions is a warning that the era of “Macs don’t get malware” is over; the systems that thrive in this new landscape will be those that assume compromise is possible and prepare accordingly.
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*This article was researched with the help of AI, with human editors creating the final content.
