Be careful with free file converters

Pitfalls from downloaded files

Mr. Nguyen Hoang - an advertising employee in Nha Trang said that after downloading a converted PDF file from a free file conversion website, his computer started running slowly, constantly showing warnings from anti-virus software. "I didn't expect using a free file conversion tool to cause such trouble," Mr. Hoang shared.

Cybersecurity experts from the Department of Cyber ​​Security and High-Tech Crime Prevention - Provincial Police warn that many online file conversion services, especially those of unknown origin, can embed malicious code into the resulting file. A seemingly harmless PDF file can contain trojans, spyware, or ransomware - "silent enemies" that destroy devices. Spyware can silently record every keystroke, from banking passwords to personal messages. More dangerously, ransomware can lock data and demand ransom in cryptocurrencies, putting users in a dilemma. According to the latest report from the National Cyber ​​Security Monitoring Center (NCSC), in the first quarter of 2025, Vietnam recorded more than 15,000 ransomware attacks, causing estimated damage of billions of VND, an increase of 20% compared to the same period in 2024.

Be careful when using free online file converters. Illustration photo

When a user uploads a file for conversion, whether it is a business contract, invoice, or photo of an ID, information such as name, citizen identification number, address, or bank account is at risk of being extracted without the user's knowledge. Many untrustworthy websites do not have clear privacy policies, turning user data into "commodities" on the "dark" web market. A set of personal information, including email, phone number, and password, can be sold for as little as $1-2, but the consequences for the victim are unpredictable: from scam messages, fake identities, to bank account hijacking.

Another common trick is to create fake URLs. Hackers often copy the interface of reputable services, changing a small character in the web address, such as changing from “convertio.co” to “c0nvertio.co” to fool unsuspecting users. Just one wrong click can lead to downloading a malicious file or accidentally providing information to bad guys. According to statistics from Google Safe Browsing in early 2025, more than 10 million visits per month globally poured into these types of scam websites, of which Vietnam was in the top 10 countries heavily affected. The free-for-all mentality of many Vietnamese people inadvertently creates opportunities for bad guys to take advantage. Warning signs for these websites include: No contact information, no clear privacy policy, or requiring users to install additional software before using. Some fake websites also use artificial intelligence (AI) to analyze user data and automatically create phishing campaigns. For example, after collecting information from user-uploaded files, bad guys can send fake bank emails or personalized SMS messages, making it easy for users to fall into the trap.

Protect yourself in the digital world

To protect themselves, users should use online file conversion services from major brands such as Adobe Acrobat Online, SmallPDF, ILovePDF, which have strict security policies and are highly rated for safety; do not convert files containing important information such as contracts, identification documents. Users should use offline software such as Microsoft Office, LibreOffice, or Foxit Reader. At the same time, always carefully review the URL before clicking, use tools such as Google Safe Browsing or VirusTotal to verify safety; install anti-virus software such as Kaspersky, Malwarebytes, Bitdefender that can detect and neutralize malware from downloaded files; ensure that the operating system and software on the device are always updated with the latest security patches to minimize vulnerabilities; regularly back up important data to an external hard drive or reputable cloud services such as Google Drive, Dropbox to avoid loss if attacked by ransomware.

JACKIE CHAN

Source: https://baokhanhhoa.vn/xa-hoi/202504/can-trongvoi-cong-cu-chuyen-doi-file-mien-phi-14d3abb/