I'm not an expert, just someone that likes spiders, but it looks to me like a false button spider (steatoda-borealis). It's just a little hard to tell for sure from the angle of this photo. Fake buttons most of the time have a "T"-shaped marking atop their abdomen that sits quite close to their cepholothorax. They're medically insignificant, however, they do quite closely resemble button spiders (hence the name), the two species of which we commonly get here in SA have quite potent neurotoxic venom. The only way I've learned to tell the difference is that the venemous ones will typically have an orange marking underneath their abdomen, and won't have that "T" shaped marking. In case it is a real button spider, I recommend you don't try to check.