10 Hacker Groups running a flaw in Microsoft's software
Cybersecurity company ESET said in a blog post: At least 10 different hacking groups use newly discovered flaws in Microsoft's Exchange Server mail server program to break into targets around the world.
The scale of the exploitation makes the warnings issued by authorities in the United States and Europe even more urgent about vulnerabilities in the Microsoft Exchange program.
Security vulnerabilities in widely used Exchange Server software leave the door open to cyber espionage, allowing malicious actors to steal email messages as they like from vulnerable servers or move elsewhere in the network.
Reuters reported last week that tens of thousands of organizations have been compromised, and new victims are announced every day.
The Norwegian parliament announced that the data had been extracted in a breach linked to Microsoft's flaws, and the German cybersecurity watchdog said: Two federal authorities were affected by the breach.
And while Microsoft has released fixes, the slow pace of update - which experts partly attribute to the complexity of the Exchange Server architecture - means that the domain remains at least partially open to hackers of all domains.
The patches do not remove any access to the back doors installed across devices, and in addition, some back doors within the compromised devices contain easy-to-guess passwords that newcomers can take over.
Although hacking appears to focus on cyber espionage, experts are concerned about the potential for cybercriminals seeking ransom to take advantage of flaws as it could lead to widespread disruption.
ESET reported that there are signs of exploitation as a group specializing in stealing computer resources for cryptocurrency mining has broken into vulnerable servers in order to spread its malware.
ESET named nine other hacker groups focused on espionage that they said are taking advantage of flaws to break into targeted networks.
Microsoft blamed the hack on China, but the Chinese government denies any role.
Several hacking groups appeared to be aware of the vulnerability before Microsoft announced it on March 2.
It is not uncommon for many different cyber espionage groups to have access to the same information before it is made public.
It appears that the information was either leaked in some way prior to Microsoft's announcement or was found by an outside party providing the vulnerability information to the Internet spies.
Cybersecurity firm FireEye said it had also seen multiple potential Chinese hacker groups using Microsoft's flaws in different waves.
The security industry is rife with theories, including the hacking of Microsoft's bug-tracking systems, which has happened in the past.