NaviSite is the most reliable hosting company site for April 2008.

NaviSite was incorporated in 1998 and provides application solutions and hosting services using its web infrastructure platforms in 18 data centers. The company recently announced an alliance with Intel Corporation to offer a suite of managed services through Intel's value added reseller community.

NaviSite's performance is followed by DataPipe, which made 11 appearances in the top ten last year. Last month's most reliable hosting company site, INetU, appears in third place this month.

Three of April's top ten hosting companies, including NaviSite, run Linux on their main sites, while another three use FreeBSD. One company uses Windows Server 2003.

Several SourceForge, Inc sites, including the popular technology news site Slashdot have been offline for several hours today.

All of Netcraft's globally distributed performance monitors have recorded a solid period of downtime at a number of sites hosted in the VA Software netblock. VA Software is the former name of SourceForge, Inc, which hosts all of the affected sites, including Slashdot, the source code repository SourceForge.net, software release site Freshmeat and merchandise supplier ThinkGeek.

Static uptime graph for www.slashdot.org

Netcraft's live monitoring of www.slashdot.org can be seen here, reflecting a contiguous outage of approximately 5 hours.

While Clinton and Obama are battling it out in the political arena, security researchers are continuing to find vulnerabilities in the candidates' and supporters' websites. Interestingly, while a typical exploit is to redirect one party's site to their opponent's, the reasons for seeking to discover such vulnerabilities are not always politically motivated.

Following the recent cross-site scripting attacks against Barack Obama's website, Finnish security researcher Harry Sintonen has published an example of a cross-site scripting vulnerability on votehillary.org.

Sintonen's example submits a POST request to the Vote Hillary website and injects an iframe, causing the site to display the contents of Barack Obama's website. Unlike the Obama incident, which redirected the user's web browser, Sintonen's method retains the votehillary.org URL in the address bar while displaying the opposing website.

Sintonen told Netcraft that he was inspired by the recent Obama attacks and first examined Hillary Clinton's official website at www.hillaryclinton.com. Sintonen did not find any cross-site scripting vulnerabilities on this site, adding that it looked quite secure, but subsequently found XSS opportunities available on the Vote Hillary website. Sintonen lives in Finland and has no strong interest in US politics.

While the example exploits have so far been relatively benign (limited to redirecting a user to the opponent's website, for example), future cross-site scripting vulnerabilities found on political candidate sites have plenty of scope to be much more serious. Obama's and Clinton's websites both accept monetary contributions towards their campaigns, so cross-site scripting vulnerabilities could be leveraged to steal money and identities from supporters.

Sintonen told Netcraft he informed the webmasters of votehillary.org about this cross-site scripting vulnerability two days ago, but has not yet received a response.

The CNN News website has twice been affected since an earlier distributed denial of service attack last Thursday. CNN fixed Thursday's attack by limiting the number of users who could access the site from specific geographical areas.

Subsequently, an attack was purportedly organised to start on Saturday 19th April, but cancelled. However, our performance monitoring graph shows CNN's website suffered downtime within a 3 hour period on Sunday morning, followed by other anomalous activity on Monday morning, where response times were greatly inflated.

Netcraft is continuing to monitor the CNN News website. Live uptime graphs can be viewed here.

A security weakness in Barack Obama's website has been exploited to redirect visitors to Hillary Clinton's website. Visitors who viewed the Community Blogs section of the site were instead presented with Clinton's website as a result of a cross-site scripting vulnerability.

Barack Obama's visitors were redirected to this site.

A user named Mox, from Liverpool, IL, posted an apparent confession in the Community Blogs section on the Barack Obama website yesterday. The subject of the post was, "I am the one who "hacked" Obamas site."

Mox plays down the matter by saying that all he did was exploit some poorly written HTML code before suggesting that it was a cross-site scripting vulnerability that had been exploited. By allowing users to enter characters such as > and " into their blog URLs, JavaScript could be injected into pages in the Community Blogs section and would be executed by subsequent visitors.

A YouTube clip from zennie62 demonstrates the attack. The clip shows a user clicking on the Community Blogs section of the Barack Obama site, which subsequently causes the browser to redirect to hillaryclinton.com. The author speculates that "Senator Clinton's staffers possibly hired someone to hack into the Barack Obama website system." No evidence is offered to back up this statement.

Another vulnerability found on the Barack Obama site.

While Mox states that the original issue has now been fixed, a number of similar vulnerabilities have since been identified and remain unfixed, and are documented on xssed.com, which notes that such vulnerabilities open up opportunities to infect Obama's supporters and site visitors with malware, adware and spyware.