By Takanori Nishiyama
WhatsApp’s contact-discovery API study is a stark illustration of how platform convenience can quickly become a large-scale privacy and attack-surface risk. In enumerating 3.5 billion active WhatsApp accounts by abusing an un-rate-limited API, researchers were able to exploit a capability that yields phone numbers, profile photos, “about” text and device metadata. When more than nine in ten people in markets like Malaysia and Indonesia rely on WhatsApp daily, a single vulnerability like this can ripple across the entire region.
End users need to treat their WhatsApp account like any other sensitive online account. That means enabling two-step verification and adding a recovery email to stop account takeover via SMS codes. Users should also make full use of the available privacy settings by limiting their profile photos and about information to “My contacts” only.
Users should also avoid publicly linking their WhatsApp number to other public profiles. It’s important to be highly vigilant about any unsolicited messages that request codes or urgent payments. Instead of replying directly, verify the authenticity of a message first, b and never share verification codes.
Cybersecurity professionals need to regard APIs as a potentially significant Achilles heel. APIs are designed for scale and automation – the same properties cybercriminals routinely look to exploit. Responsible vulnerability disclosure and timely patching help, but platform-level fixes must be paired with threat-detection and anomaly-blocking to prevent successful mass harvesting.
Organisations should never assume end-to-end encryption as a guarantee of regulatory safety. They should create clear bring-your-own-device and instant messaging policies that define permitted use, particularly where regulated data or client communications are involved.
Implementing enterprise mobility management controls, data-loss prevention and enterprise-approved secure messaging for official communications is also strongly recommended. Moreover, C-suite and front-line staff should be trained on social-engineering risks seeded from scraped datasets to reduce the potential for human error.
Organisations also need to prioritise plans for containment. Even if a messaging-related compromise occurs, robust privileged access management and zero-trust controls can drastically minimise the blast radius.
Enforcing least-privilege access, rotating credentials, verifying every user and device, and segmenting access pathways ensures that a compromised account or harvested contact data cannot be used as a pivot into high-value systems. These controls turn what could become a full-scale breach into a contained, low-impact incident.
WhatsApp remains hugely widespread across APAC, so threats here are not hypothetical – the scale of exposure means both individual hygiene and organisational controls must be treated as core cyber risk, not an optional convenience.
The author is SVP APAC & Japan Country Manager, Keeper Security. Views are personal.
