The Syrian Electronic Army (SEA), a political hacktivist group, said it hacked Paypal and eBay domains in the UK, France and Israel on 1 February.
The hackers said the attack was considered as a "hacktivist operation" and that account information was not targeted.
They also said the operation wanted to highlight how both firms have no presence in Syria, and the impact that has had on its people.
According to reports, the websites were affected for around an hour, and the SEA said that it hoped PayPal and eBay users "learned a lesson".
The SEA Twitter account, @Official_SEA16, tweeted: "If your Paypal account is down for a few minutes, think about Syrians who were denied online payments for more than 3 years. #SEA"
A spokesperson from the jointly-owned companies said: "No customer data was accessed by these redirects, and no customer accounts were affected. We take the security and privacy of our customers very seriously and are actively investigating the reasons behind the temporary redirects."
The SEA has become known for high-profile attacks, usually on western media companies. The hackings are performed through phishing, or fraudulent emails used to trick the company’s employees into providing sensitive login information.
At the time of writing, SEA’s official Twitter account had been suspended following the attack on eBay and PayPal.
Twitter user and SEA member @SEATh3Pr0 said: Twitter suspended our main account (@Official_SEA16). We are working to bring it back if it’s possible, for now follow @SEA_Official17 #SEA.