Chief executive Kevin Mandia said in a blog post on Sunday (Monday AEDT) that the compromise was executed through the Orion network monitoring product sold by SolarWinds.
Small detail from Solarwinds 8K SEC filing which is worth pulling out - it was the build server which inserted the backdoor.— Kevin Beaumont (@GossiTheDog) December 14, 2020
See also Ccleaner.
The product has extremely wide usage, with 400 of the so-called Fortune 500, and the top telcos, the US military, the US State Department, the NSA and the Office of the President of the US, all using the same NMS.
Mandia described the attackers as having the best operational tradecraft and resourcing similar to that which those operating on behalf of a country would have. But, unlike his tendency in the past, he stopped short of attribution.
- "Use of malicious SolarWinds update: Inserting malicious code into legitimate software updates for the Orion software that allow an attacker remote access into the victim’s environment;
- "Light malware footprint: Using limited malware to accomplish the mission while avoiding detection;
- "Prioritisation of stealth: Going to significant lengths to observe and blend into normal network activity; and
- "High OPSEC: Patiently conducting reconnaissance, consistently covering their tracks, and using difficult-to-attribute tools."
The last time malware was spread by compromising updates was in the case of CCleaner, software from security vendor Avast that allows Windows users to perform routine maintenance on their systems.
Earlier on Sunday, there were reports that attackers had compromised the US Treasury Department and other government agencies, with Microsoft Office 365 being blamed for the intrusion.
Mandia did not say definitely that the attacks he described had also included one on his own company, but anyone reading his post would have drawn just that very conclusion.
He said numerous organisations had been identified as being affected, going right back to the western spring of 2020 and they had been notified.
"Our analysis indicates that these compromises are not self-propagating; each of the attacks require meticulous planning and manual interaction," Mandia said. "Our ongoing investigation uncovered this campaign, and we are sharing this information consistent with our standard practice.
"We have been in close co-ordination with SolarWinds, the FBI, and other key partners. We believe it is critical to notify all our customers and the security community about this threat so organisations can take appropriate steps. As this activity is the subject of an ongoing FBI investigation, there are also limits to the information we are able to share at this time."