A company providing online payment-processing services for U.S. Rep. Joe Wilson (R-S.C) is back online after being disrupted by a distributed denial-of service attack over the weekend.

The attack on Piryx began Friday afternoon and lasted into the early hours of Saturday morning and temporarily disrupted a Wilson fundraising effort that was underway at that time. Piryx CEO Tom Serres said. It also knocked out services for about 150 other Piryx clients, Serres said.

Piryx is a nonpartisan Austin, Texas, based start-up that provides services to help political candidates and nonprofits manage online campaigns and fundraising.

Serres said the company was contacted by Wilson's office last week and asked to manage online donations from supporters rallying behind the congressman after he shouted "You lie!" during President Obama's address to Congress on health care reform Wednesday.

Hours after the company began hosting Wilson's homepage on its servers, Piryx found itself the target of a distributed denial of service attack, Serres said. Such attacks are designed to render servers and networks inaccessible by flooding them with useless traffic.

The attacks appear to have been directed at the joewilsonforcongress.com site, Serres said. At the time the attacks started, the site was handling about 100 transactions per minute and had already collected more than $100,000 from people who wanted to contribute to Wilson's campaign, he said.

Initially, the traffic generated by the DDoS attack was manageable but soon Piryx began noticing "massive bandwidth spikes" that knocked its servers offline, Serres said. The data center hosting Piryx's servers confirmed that it was the victim of a DDoS attack. At its peak, the DDoS flood generated about 1 gigabit of traffic per second, which is about 1,000 times the normal traffic on Piryx, Serres said.

After several failed attempts at mitigating the attacks, filters to block the traffic went into place early Saturday morning. Service has been normal since then, he said. It's not known from where the attacks originated, but Serres said it appears to have been initiated by those opposed to Wilson's comments, he said. "It was clearly politically motivated to take down Wilson's ability to raise funds online," Serres said.

The incident appears to be one of the rare instances of a politically motivated attack against a Web site in the U.S. said Kirsten Dennesen, an intelligence analyst with Verisign Inc.'s iDefense Labs. The attention attracted by Wilson's comments, especially through social media tools such as Facebook and Twitter, appears to have contributed to the attack, she said.

"One question is whether there are going to be any response attacks," she said.

Everyone has seen a fake virus infection Web page from time to time. They pop up on your screen looking like a perfectly normal Windows page except they tell you that your PC is infected by a virus and you need to click here to either fix the problem or download a program that will clean out the bug for you. The only problem is it's a lie. It's actually an attack designed to get you to download malware.

Usually these fake Windows pages-they're actually Web pages-pop up when you're visiting a dodgy Web site. But, even the New York Times isn't immune to attacks like this. Over this last weekend, September 12-13, I was startled to see an apparent Windows page show up that read, "Warning!!! Your system requires immediate anti-viruses scan. Personal Antivirus can perform fast and free virus malicious software scan of your computer."

Now, I wouldn't fall for this, but I can see how many people would. At a glance, it looks real and the last thing most people expect to see coming from the New York Times is malware. But, that's exactly what it was.

The paper confessed to the problem stating that "NYTimes.com readers have seen a pop-up box warning them about a virus and directing them to a site that claims to offer antivirus software. We believe this was generated by an unauthorized advertisement and are working to prevent the problem from recurring. If you see such a warning, we suggest that you not click on it. Instead, quit and restart your Web browser."

That's good advice. When you're on a Windows PC, you shouldn't click on any part of the fake message. No, not even cancel. Any click might start a malware download.

In the event, this particular attacker was even cruder. If you clicked on it, you wouldn't get malware, you'd get an endless series of scareware messages until you either rid yourself of the program or 'buy' the software by entering your credit-card number. After that, you might as well call up your credit-card number and get a new card. Your credit card information has just been stolen.

The Times has dealt with the problem on their end, so you won't see this particular nuisance from their site again. But, the iFrame injection attack behind that fake page is an extremely common kind of XSS (cross site scripting) attack.

Since the problem starts at either a compromised or, in the case of the NYT tricked, Web site, there's not a lot you can do to prevent the attack on your side.