A hacker claims to have infiltrated the systems of the Clinton Foundation, and has released documents revealing donations made to the Democratic National Party.

The security breach was carried out by Guccifer 2.0, who is believed to be a cover for intelligence agents from Russia. The target is a non-profit organization that Hillary Clinton, the Democratic presidential candidate for the upcoming United States elections, founded with her family.

According to a blog post by Guccifer 2.0, he was able to hack the servers of the Clinton Foundation and download hundreds of thousands of documents and databases of donors. The hacker claimed that Clinton, along with her staff, do not bother with information security, allowing for the security breach to happen.

"As you can see, the private server of the Clinton clan contains docs and donors lists of the Democratic committees, PACs, etc. Does it surprise you?" Guccifer 2.0 wrote.

One of the documents discovered by the hacker reveals that certain banks are donating some funds that were received from the Troubled Asset Relief Program to the Democratic party. In another document that was uploaded, donors to the Clinton Foundation from 2009 to 2015 were listed, with some of them being Google CEO Eric Schmidt, Microsoft founder Bill Gates, Microsoft VP Steve Ballmer and Hollywood celebrities such as Tom Hanks and James Brolin.

An official of the Clinton Foundation, however, denied that a security breach occurred, with the files uploaded by Guccifer 2.0 not coming from the foundation.

"Once again, we still have no evidence Clinton Foundation systems were breached and have not been notified by law enforcement of an issue," the official stated.

A person who is familiar with the documents told Politico that the files look like they came from the Democratic Congressional Campaign Committee, which was the subject of a hacking attack earlier this year. There are several signs that the documents originated from the DCCC, including notes found in some of the files that seem to have been written by the rapid response director of the committee.

Other signs include the similarities between the donors in the documents to contributors to the DCCC, the mismatch of donors to the list on the Clinton Foundation website, and the fact that one of the spreadsheets was created by a staffer of the DCCC back in 2009.

Clinton has been on the wrong end of information security problems through her campaign, and has received criticism on how she has handled classified information since she was Secretary of State.