Security News

Microsoft says Beijing-backed hackers are exploiting four zero-day vulnerabilities in Exchange Server to steal data from US-based defense contractors, law firms, and infectious disease researchers. Gain access to an Exchange Server either using stolen passwords or by using zero-day vulnerabilities, and disguise themselves as a legitimate user.

Microsoft has released emergency patches to address four previously undisclosed security flaws in Exchange Server that it says are being actively exploited by a new Chinese state-sponsored threat actor with the goal of perpetrating data theft. Describing the attacks as "Limited and targeted," Microsoft Threat Intelligence Center said the adversary used these vulnerabilities to access on-premises Exchange servers, in turn granting access to email accounts and paving the way for the installation of additional malware to facilitate long-term access to victim environments.

Microsoft late Tuesday raised the alarm after discovering Chinese cyber-espionage operators chaining multiple zero-day exploits to siphon e-mail data from corporate Microsoft Exchange servers. In all, Microsoft said the attacker chained four zero-days into a malware cocktail targeting its Exchange Server product.

Microsoft has released emergency out-of-band security updates for all supported Microsoft Exchange versions that fix four zero-day vulnerabilities actively exploited in targeted attacks. These four zero-day vulnerabilities are chained together to gain access to Microsoft Exchange servers, steal email, and plant further malware for increased access to the network.

Microsoft Corp. today released software updates to plug four security holes that attackers have been using to plunder email communications at companies that use its Exchange Server products. The patches released today fix security problems in Microsoft Exchange Server 2013, 2016 and 2019.

"Customer needs are changing, and so are the ways in which financial institutions need to interact with them," said Wayne Busch, President Financial Services and Insurance, NTT DATA Services. "Advancements in artificial intelligence, machine learning and data intelligence are giving banks vast capabilities to deliver what customers want - hyper-individualized, relevant and timely financial guidance to achieve their life ambitions."

Threat actors downloaded some Microsoft Exchange and Azure code repositories during the sprawling SolarWinds supply-chain attack but did not use the company's internal systems or products to attack other victims. "We have now completed our internal investigation into the activity of the actor which confirms that we found no evidence of access to production services or customer data," the company said in a blog post on its Microsoft Security Response Center published Thursday.

Microsoft has completed its internal investigation about the Solorigate security incident, and has discovered that the attackers were very interested in the code of various Microsoft solutions. The attackers viewed some files here and there, but they also managed to download source code from a "Small number of repositories," and this includes the code for some important Microsoft Azure components.

Microsoft has admitted that as a result of installing backdoored SolarWinds tools in some parts of its corporate network, portions of its source code was obtained and exfiltrated by parties unknown. "There was no case where all repositories related to any single product or service was accessed," the update advises, adding: "There was no access to the vast majority of source code. For nearly all of code repositories accessed, only a few individual files were viewed as a result of a repository search."

Microsoft on Thursday said it concluded its probe into the SolarWinds hack, finding that the attackers stole some source code but confirmed there's no evidence that they abused its internal systems to target other companies or gained access to production services or customer data. The disclosure builds upon an earlier update on December 31, 2020, that uncovered a compromise of its own network to view source code related to its products and services.