A new report indicates Chinese state-sponsored cyber espionage groups ‘Winnti Umbrella’ linked in a number of cyber campaigns from 2009 to 2018 targeted Gaming studios and Software companies in South Korea, United States, Japan, and China.
According to ProtectWise report the threats actors attacks against small organizations to exfiltrate the codesigning certificates and to use them in signing malware for use in high profile attacks.
The name “Winnti” used to refer the backdoor that created by the hacker groups that linked under the umbrella. In 2013 Kaspersky published a report on the original Winnti group and the technical details associated with it.
Researchers believe all the groups under Winnti umbrella share the same tactics, techniques, and procedures (TTPs) and also their testing environments.
Attack Methods – Winnti Umbrella
The Winnti umbrella and associated groups initial infections are through phishing to gain access to the target organization. In 2018 their campaigns primarily targeted on common services such as Office 365 and Gmail. With their most recent campaigns, they preferred using URL shortening service.
Once they gained access to organization network they use custom malware and tools like Metasploit and use number of techniques such as “living off the land” for minimizing the attack of detection.
Living off the land attack describes making use of the tools that already installed on the system or running simple scripts and shellcode directly in memory.
For C&C communication attackers use subdomains resembles target organizations and often they used abused TLS certificates from Let’s Encrypt and in many cases self-signed certificates.
“We have observed a few cases of the attackers mistakenly accessing victim machines without a proxy, potentially identifying the true location of the individual running the session. In all of these cases, the netblock was 184.108.40.206/13, the China Unicom Beijing Network, Xicheng District.”
Researchers said, “Overall the Winnti umbrella and linked groups are lacking when it comes to operational security. But some groups followed better operational security which indicates there is a division among them.”
“We hope the information we’ve shared in this report will help potential targets and known victims in addition to the greater information security community. Though they have at times been sloppy, the Winnti umbrella and its associated entities remain an advanced and potent threat” researchers concluded.