Cape Town - Internet service provider (ISP) MWEB has been hacked and the details of several of their business clients have been posted online.
It is unclear how the hacker gained access to the MWEB database, but the posting on Seclists included names and login details from various companies.
"We have 1 000 clients still on the Internet Solutions network and we are busy migrating them off that old server (which is) the one they attacked," MWEB CEO Rudi Jansen told News24.
He said that there were "a couple of weak links" that allowed the hack, but that the hacker was not able to get any personal information and the clients sustained no losses from the attack.
Nevertheless, he conceded that it was embarrassing for MWEB and was in contact with clients to advise them on what to do.
"It's never nice to be on the receiving end of an attack and we get about 5 000 hack attacks a day and this one slipped through. It's a single-use logon, so even if the attacker gets hold of the information, it doesn't matter because it's useless to them."
Jansen said that the racist overtone of the posting on Seclists was probably related to nationality of the poster, rather than the hacker.
"These guys are linked to WikiLeaks and they just post things as they come - it's probably American."
Jansen urged all internet users to be vigilant with usernames and passwords.
"We tell our clients to change their usernames and passwords regularly."
According to HackingStats, the total number of South African websites hacked so far this year is 14 119.
News24 is part of 24.com, a subsidiary of Media24, which is in the Naspers stable. MWEB is a subsidiary of Naspers.
- Follow Duncan on Twitter