(Adds details from briefing, background)
March 13 (Reuters) - Canada's federal government said on Monday that its statistics agency was hacked last week and its website plus several other government portals were taken offline to fix a major security vulnerability.
Statistics Canada took down the website late on Thursday night soon after discovering "unauthorized access" to its server, which the agency said does not contain any personal or sensitive information.
A software flaw exposed the website to hackers and the Canadian websites have since been patched and resumed operations, officials said.
While the sites, which also included the Canada Revenue Agency, had the potential to be exploited, there is no evidence that any sensitive data had been copied or removed, a Treasury Board official told a media briefing.
The tax agency going offline prevented Canadians from filing their taxes online over the weekend, but will likely not cause a delay in processing and the agency will not extend the filing deadline, it said.
A vulnerability was found in the widely used Apache (NYSE:APA) open source software that uses the Java programming language commonly used to build and maintain websites.
The flaw became widely known last week and can use "remote code execution" to add malicious files or delete legitimate ones and security researchers say it is being exploited actively and widely.