Three Anonymized Cases: Real Ransomware Incidents in Q1

In the first three months of the year, we received nearly 40% more ransomware assistance requests than in the second half of last year. Most companies’ IT leaders react first with “our firewall was expensive,” but on site the problem usually lies with the weakest plank. **Case 1: A precision manufacturing company in Shunyi** had just rolled out an MES system before the Chinese New Year holiday. The attacker entered the internal network through the system’s default Tomcat weak credentials (admin/admin123), spent three days mapping the network architecture, and triggered ransomware before the end of work on Friday. What is interesting about this company is that its internet-facing firewall policy was actually quite strict, yet the MES admin console was directly exposed on the office network segment with no secondary authentication. When encryption began, the engineers were still working through the night to meet order deadlines. **Case 2: A software company in Haidian**, small in size but with sensitive code assets. The infection path was a marketing colleague clicking a phishing email disguised as a customer inquiry, with a macro-enabled Excel attachment. The macro downloaded Cobalt Strike, and the attacker spent two weeks on internal reconnaissance, only acting in mid-March — the timing chosen because finance had just completed payments before Qingming and there was money in the account. The company’s post-incident review found that the domain controller admin password was exactly the same as the user domain admin password. **Case 3: A healthcare institution in Dongcheng**. On the night its database was ransomed, the entire appointment and registration system went down. The initial entry point was an old workstation in the radiology department, never shut down and never patched, which happened to be running VNC on port 5900. The head nurse in that department had no idea the computer was connected to the internal network and thought it was a standalone “image reading machine.” These three cases share one thing: none was a sophisticated attack; all were known risks. The only difference is whether anyone actually looked.

Initial Intrusion Paths: Your Perimeter May Be Thinner Than You Think

Based on the incidents we handled in Q1, the top three initial intrusion paths were: weak or brute-forced VPN credentials, phishing emails, and remote management ports exposed to the internet. The VPN entry point deserves a few more words. Many companies are generous when buying firewalls, but their VPN devices often still use factory default passwords, or the IT admin takes the easy route with a simple combination of a personal birthday plus the company name. The attacker does not need a 0day; once brute force succeeds, what they obtain is a “legitimate” pass into the internal network — everything looks normal in the firewall logs. On phishing, Q1 showed a clear trend: attackers are getting better and better at targeted phishing. Not the mass emails that look fake at a glance, but messages impersonating the boss, a client, or a system administrator, asking an apparently reasonable question in a convincing tone. The most outrageous case we saw: the attacker looked up the target company’s business registration information on Tianyancha, registered a phishing domain one letter different from the official website domain, and sent an “annual audit notice” to finance. As for legacy systems exposing RDP 3389 or VNC 5900 directly to the public internet, all I can say is that you never know which port will become the starting point of a nightmare. Healthcare and manufacturing are especially bad, because equipment refresh cycles in these industries are long; many critical industrial control devices are still running under maintenance contracts signed ten years ago, and the system vendors went out of business long ago. On lateral movement, mainstream ransomware groups no longer encrypt as soon as they get in; they first lie low inside the network for days to weeks. The usual approach is to harvest local passwords first, then attempt Pass-the-Hash lateral movement to the domain controller. If the domain admin password is captured, the entire AD is essentially transparent — users, machines, and policies all fall. In two cases we handled in Q1, the first thing the attackers did after gaining domain admin rights was not encryption but pulling the DHCP server configuration, to figure out which subnets existed and which services were running, and only then did they begin.

Incident Response SOP: The Six-Hour Golden Window

From the completion of encryption to full spread, a ransomware attack usually has a time window. That window may be two hours or two full days — depending on how well the corporate network architecture is segmented and on the ransomware family’s strategy. Ideally, you should complete network isolation within that window. Our incident response SOP has roughly four phases, each with clear time expectations and checklists: A few pitfalls are worth highlighting. Some corporate clients, the moment they discover ransomware, rush to pay the ransom for decryption. The most extreme case we saw went from discovery to payment in under four hours; in the end 30% of the decrypted data was corrupted, and the attacker had left a backdoor and came back a month later. Another pitfall is “thinking you have isolated the network when you have not” — some ransomware scans port 445 across the internal network, and if your switch VLANs are not properly segmented, one infected machine can take down the whole segment. A bit more on backup strategy. Several clients we handled in Q1 had backups but could not restore them. Why? Because the backup server itself was a domain member, and backup jobs ran with domain admin privileges. The first thing the attacker did upon entry was delete the backup data directory or encrypt the backup storage. This “backups inside the same AD forest” architecture is very common, and it is the most easily overlooked risk point. True offline backup should mean physical disconnection from the network, or at least an independent authentication system. Finally, the old question: should you adopt zero trust? Earlier this year we helped a smart manufacturing company deploy the sTrust Zero Trust solution, with the core goal of consolidating remote access entry points. They previously had five different VPN and remote desktop solutions, with chaotic management and scattered credentials. After zero trust was in place, all remote access must pass through a unified entry point with device authentication, and the 3389 and 5900 ports previously exposed to the public internet were all taken offline. The client later told us it felt like “the attack surface has gotten much smaller” — a plain statement, but true.

The essence of ransomware is not a technical contest but a game of cost. Attackers will repeatedly test your weak points until they find the corner that no one watches. Rather than believing “we will not be targeted,” run an attack surface review regularly and take those forgotten legacy systems, old accounts, and open ports seriously. We recommend that companies audit their IT asset exposure at least once every six months; for details, please see our Network Equipment Package service.

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