Pinterest investigates hack after pins to be replaced with photos of butts

Reports of the hack began appearing across Twitter last night
Users were complaining pins on their feeds had been replaced by spam
Images ranged from photos of bottoms to women in their underwear
Many were captioned with weight loss spam or were promoting giveaways
Hackers access boards using malicious code in 'Pin' buttons on other sites
Pinterest is aware of the problem and told MailOnline it is investigating
The site is also warning people of unusual activity on their accounts

PUBLISHED: 06:19 EST, 28 March 2014 | UPDATED: 08:25 EST, 28 March 2014

Next time you login to Pinterest, you may be met with a board full of scantily clad ladies and rows of bottoms.

Boards across the site have been hacked causing pinned photos to be replaced with spam images of women in underwear.

Some are front-facing shots, while others show clothed and bare bottoms – each captioned with weight loss spam, or giveaway offers.

Reports of the hack began appearing on Twitter last night. Tweet from Hermione Way pictured. Users were complaining pins on their feeds had been replaced with images bottoms or women in their underwear. Many were captioned with weight loss spam while others were promoting giveaways

HOW TO KEEP YOUR PINTEREST ACCOUNT SECURE

Report the pin: If you spot a spam pin, report it to Pinterest by clicking the flag icon at the bottom of the image.

Change your password: If you suspect someone has hacked your account, reset your password in Settings. Pinterest may also automatically prompt you to change your password if it notices unusual activity on your account.

Only login to official sites: These include Pinterest.com and the official mobile app.

Be careful about linking your account to other social media: If scammers gain access, they can easily share spam pins on your Twitter and Facebook feeds.

Check before you pin: Before you repin, hover on the image and check the destination link corresponds with the information on the pin.

Source: The Council of Better Business Bureaus

Reports of the hack appeared on Twitter last night, with startup expert Hermione Way and Techcrunch's co-editor Alexia Tsotsis being among those affected.

Hermione Way tweeted 'Dear @Pinterest my accounts been hacked with someone posting hundreds of butt pictures all over my boards-security??!'

The Council of Better Business Bureaus posted a warning at the start of the month about how the amount spam on the photo site was increasing.

Pinterest has been alerted to the problem and told MailOnline that it is investigating the issue.

While Pinterest aren't actively taking the pins down, users can check their account and remove any offensive hacked pins.

Pinterest has a strict policy when it comes to sexually explicit images.

However, the problem appears to be on other websites that host 'Pin this' buttons, rather than Pinterest directly.

Many websites feature the button, alongside other share options, on articles and images.

Hackers are infiltrating these websites and inserting malicious codes into these third-party 'Pin this' buttons.

Pinterest has been alerted to the problem and is investigating the issue. The problem appears to be lying on other websites that host 'Pin this' buttons. Hackers are infiltrating these websites and inserting malicious codes that swap pinned images for links to spam, pictured

Following a rise in spam, Pinterest has started warning users of unusual activity on their accounts when they log in, and suggesting they reset their password. Warning message pictured

When a user clicks the button to pin a particular image, the code replaces it with spam.

Due to the rise in spam, Pinterest has started warning users of unusual activity on their accounts when they log in, and suggesting they reset their password.

Other hackers are creating fake boards designed as phishing scams that attempt to get access to connected Facebook accounts, for example.

At the start of March, Twitter accidentally reset millions of user's passwords but claimed it was due to a software bug, and wasn't because the site had been hacked.

More recently, a number of Twitter accounts started automatically following thousands of other users and it was believed to have been caused by an infected, linked app.