Either the Iranians truly hate Twitter, or someone wants us to think they do.

At about 10 p.m. yesterday, the Twitter homepage was hacked; instead of its usual "What's happening?" message, people were greeted with the below image.

The message read:

Iranian Cyber Army

THIS SITE HAS BEEN HACKED BY IRANIAN CYBER ARMY

iRANiAN.CYBER.ARMY@GMAiL.COM

U.S.A. Think They Controlling And Managing Internet By Their Access, But They Don't, We Control And Manage Internet By Our Power, So Do Not Try To Stimulation Iranian Peoples To ............

NOW WHICH COUNTRY IN EMBARGO LIST? IRAN?USA?

WE PUSH THEM IN EMBARGO LIST ;)

Take Care.

According to Praetorian Prefect, the additional three-part text translates roughly to "Hezbollah is victorious"; the name of the third Shi'i Imam, Imam Husayn; and, "We shall strike if the leader orders, we shall lose our heads if the leader wishes."

At 11:43 p.m., Biz Stone blogged about a DNS disruption: "As we tweeted a bit ago, Twitter's DNS records were temporarily compromised tonight but have now been fixed. As some noticed, Twitter.com was redirected for a while but API and platform applications were working. We will update with more information and details once we've investigated more fully." No word since then.

The same hack still appears on mowjcamp.org, a site in support of Mir-Hossein Mousavi Khameneh, who ran against Mahmoud Ahmadinejad in the 2009 Iranian presidential election. It's been there since Wednesday.

It was during that election, of course, that Twitter came to prominence as a tool for political action, when Iranian citizens used it to disseminate information about and during protests following what were believed to be fraudulent results. When in-country reporting was banned, media outlets used Twitter feeds to gather both news and photos.

The Google index was also affected, reading, "This Web Site Has Been Hacked By The Iranian Cyber Army." The site description, in Farsi, reads, "In the name of God, As an Iranian this is a reaction to Twitter's interference sly which was U.S. authorities ordered in the internal affairs of my country ..."

There's still no word for the reason behind the attack -- which has earned its own genre: "hacktivism" -- or the timing of it. PCWorld reports that the group was previously unknown, and quotes Graham Cluley, from the Sophos security firm, as saying that this "does not necessarily mean that hackers from Iran are responsible for the defacement."

The attack appears to be a DNS redirect, which, says Pretorean Prefect, appears to be coming from Provo, Utah.

Update: TechCrunch is reporting that the attack originated from a group working with the Iranian government. They confirm that it was a redirect attack, meaning users trying to access the Twitter page were sent elsewhere; the twitter.com domain was not itself compromised.

Update 2: TechCrunch also has a more in-depth look at how the attack dovetails with a larger Iranian strategy.

Update 3: Biz Stone has updated the Twitter blog with more details of the attack:

Domain Name System or DNS is an Internet protocol used to translate IP addresses into domain names so instead of typing in a long string of numbers we can enter urls like www.twitter.com into a browser to visit our favorite web sites. Last night, DNS settings for the Twitter web site were hijacked. From 9:46pm to 11pm PST, approximately 80% of Traffic to Twitter.com was redirected to other web sites. We tweeted, blogged, and updated our status page last night.

During the attack, we were in direct contact with our DNS provider, Dynect. We worked closely to reset our DNS as quickly as possible. The motive for this attack appears to have been focused on defacing our site, not aimed at users—we don't believe any accounts were compromised. If you're concerned that your account could have been affected in some way, feel free to contact us, accountsafe [at] twitter.com.

(Via TechCrunch, via @Orli.)