Day: May 4, 2026

A Ransomware Nightmare Triggered by a “Silent Printer” In late autumn 2019, Lao Zhou, the IT manager at a tech company in Wangjing, received an urgent call from the sales team — all the printers had “gone on strike” at the same time, and the screens showed an encrypted message demanding 0.5 Bitcoin for the decryption key. Even stranger, the company’s file server also showed abnormal access logs that same night. Lao Zhou investigated for two full days, …

The conference room disconnect nightmare Last Wednesday afternoon, a partner at a law firm in Tuanjiehu walked out of a third-floor meeting room with a MacBook, taking a conference call on the move. At the corridor corner, the Wi-Fi signal dropped for a full six seconds—the person on the other end thought he had hung up. I have seen this scenario more than twenty times. The problem is usually not insufficient AP coverage, but poorly tuned roaming decision logic: the client hesitates between two APs and finally picks…

Last winter, the owner of an auto-parts mold company in Shunyi came to me. He said his team of about twenty people was using a hand-assembled PC as a file server. It blue-screened every few days, and mold drawings were constantly deleted by accident. The machine had been running for nearly six years, nobody knew the password, and it held over a hundred GB of historical data. The first question he asked me was: is moving to the cloud the least troublesome option? He is not the only one asking this. Over the years I have worked with…

Why choosing the wrong DNS can take an entire office offline during afternoon tea. Last year we handled an incident for an auto-parts export company in Shunyi. When the engineer arrived on site, more than twenty computers in the office could not open the client’s quotation system. After checking around, it turned out the network was not down — DNS resolution was timing out. They were using broadband set up by their landlord, and the DNS server was 202.106.0.20 from a local carrier, and responses…

Authentication: from static credentials to continuous trust evaluation. Traditional VPNs rely on usernames and passwords plus static certificates, and once authentication passes, the user gets full network permissions. That “verify once, allow forever” model already looks quite dangerous in 2024. I have seen more than one company’s VPN taken down by credential-stuffing attacks, with the attacker following the tunnel straight into the internal finance system. They do not even need privilege escalation, they just…