An attack of malware hit an advertising server for Yahoo over the past couple of days, affecting thousands of Internet users that use the platform. The users affected were in different countries, said a security firm on the Internet.
Fox-It, in its blog post, said that Yahoo servers had been releasing an exploit kit, which helped exploit the vulnerabilities in Java and in installed malware.
The security firm wrote that clients that visited yahoo.com received ads that were served by ads.yahoo.com. Some of the ads said the security firm were malicious.
Fox-IT said the typical rate of infection was 9%, which would result in each hour approximately 27,000 new infections. Based upon that same sample, the different countries that had been affected the most due to the exploit kits were Great Britain, France and Romania.
However, currently it remains unclear as to why those particular countries were most affected. Likely, said the security firm, it was due to configurations of malicious ads on Yahoo.
If a computer that is infected with that malware is connected to a particular network, the attackers can often times access the other connected servers and systems.
Yahoo attached it had not been aware of the issue over security. A statement released by the Internet giants said they take the privacy and safety of all their users very seriously.
Yahoo continued by saying it had recently identified ads that were designed to distribute malware to some users. The ads were removed immediately and the site is being monitored continuously to block any other ads being used to carry out that activity.
The cyber security firm announced it was unclear who had been responsible for the malware attack, but it appeared as if it had been financially motivated, but did not provide any details.
The investigation revealed that the first sign of any infections was back in late December on December 30.