Warning about WhatsApp voice notes in South Africa
South Africans are being cautioned to be aware of their surroundings when answering their cell phones or sending voice notes, as cybercriminals are increasingly stealing voice biometrics.
This is a message from Andrew Bourne, Regional Manager for Zoho Corporation Africa, a multinational technology company specialised in business software.
Speaking to CapeTalk, he explained that many South Africans are unaware of just how valuable their voices have become to cybercriminals.
According to Bourne, one of the simplest ways criminals can capture a person’s voice is through silent calls.
“When you pick up the phone, say hello, hello, hello, and there’s no one on the other side, it could be more than just a dropped call. What in fact could be happening is that criminal organisations are aggregating data,” he said.
“They might already have your ID number and phone number from a previous data leak, and by capturing your voice, they’re confirming that you’re still using that number. This keeps their databases up to date and more valuable.”
While saying “hello” might not be enough to generate a convincing fake voice, Bourne noted that repeated recordings from social media, calls, or voice notes could give criminals enough material to create deepfake audio.
“If you were a targeted person, they could research and compile recordings of your voice to create a realistic deepfake,” he said.
“That’s why awareness and education are so important. People need to know that these aren’t just harmless calls.”
Bourne added that criminals use this harvested data in various ways, from selling it to the highest bidder to carrying out specific scams. “It’s all about building a holistic picture of someone’s online activity,” he said.
“That data can then be used for fraud, extortion, or what’s known as whaling – going after high-profile individuals.”
He gave the example of extortion scams where criminals may use harvested voice data to fake distressing and urgent scenarios.
“You might get a call where you hear your child asking for help. In reality, they could have lifted your child’s vocal biometrics from a video on social media or from a hacked app. It’s a terrifying thought, but it shows how creative criminals can be.”
Be vigilant
To protect themselves, Bourne urged ordinary people to be more cautious when handling calls and sharing personal information.
“If someone phones you and claims they have your ID number, don’t just trust them. Ask them to prove who they are—ask what bank account this is about or for details only your institution would know,” he said.
He also advised families to set up a safe word so that if they ever face a distress call or potential extortion attempt, they can verify authenticity.
Bourne pointed out that scams are becoming increasingly sophisticated. He highlighted a case in Hong Kong where scammers used a deepfake video of a CEO to trick an employee into transferring $25 million.
“This is the level of fraud we are dealing with. It’s not just about your data being stolen; it’s about how criminals use it in ways that feel very real and very convincing,” he said.
Even everyday tools like WhatsApp voice notes come with risks. When asked whether sending voice notes was safe, given WhatsApp’s end-to-end encryption, Bourne said they still carry some risk.
“Encryption is great and keeps things secure to a certain degree, but it doesn’t stop someone from sharing your voice note with a third party or re-recording it. Once your voice is out there, it can be copied and reused.”
Bourne urged South Africans to be vigilant. “It might feel rude not to answer calls, or paranoid to question someone claiming to be from your bank, but these small steps can protect you,” he said.
“Awareness and digital literacy are our best defences against increasingly advanced scams that target not just our data, but our very voices.”
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