In a 2 November advisory reported by 8world, police warned that opening WhatsApp attachments disguised as work documents on a computer can install malware.
The messages come from hijacked accounts belonging to friends, colleagues or supervisors.
Files Come With Instructions to Open Them on a Computer
Recipients are told to open the attachments on a computer. Some are also asked to forward them to their company’s finance manager.
Opening one of these files can let malware onto the computer, where it logs what the user types, takes screenshots and connects to a server run by the attackers.
Scammers may then hijack victims’ WhatsApp accounts to distribute more malicious files or impersonate them to borrow money.
Police had received no reports of financial losses as at the advisory, but warned that personal data could have been stolen.
Verify Unexpected Attachments Before Opening Them
The Singapore Cyber Emergency Response Team (SingCERT) issued a related advisory on 28 October.
Depending on the malware, attackers could steal login details, monitor online banking and hijack WhatsApp Web sessions.
SingCERT advises users to avoid unexpected attachments, including those from familiar contacts. Call the sender through another trusted channel to verify the file first.
It also flagged files ending in .exe, .iso or .zip as potentially containing malware.
Already Opened a Suspicious File?
SingCERT says the computer should be cut off from the network and checked with antivirus software, and contacts should be told not to open any files that came from your account.
Check WhatsApp’s linked devices, sign out of unfamiliar sessions and enable two-step verification. Until the computer has been cleaned up, stay off WhatsApp Web and other sensitive accounts on it.
Report unauthorised banking transactions to your bank and police immediately. Anyone unsure about a possible scam can call the 24-hour ScamShield helpline at 1799.
