Social media, including platforms such as Instagram or WeChat, has transformed several aspects our lives, ranging from global social interaction towards disrupted attentional patterns. Here, we explored how social media becomes a salient distractor intruding into global and local attention and the underlying neural pathways by means of functional magnetic resonance imaging (fMRI). Thirty-eight participants underwent a global-local attention paradigm combined with online social information distraction (SD), online nonsocial information distraction (NSD), and without information disturbance (baseline: BL). Results showed that SD decreased accuracy during both global and local attention processing. In contrast, NSD primarily decreased accuracy during global attention processing. On the neural level the SD effects were mirrored in decreased engagement of a core posterior default mode network node (DMN), i.e. the left precuneus. The effects at the network level were mirrored by the core region of the posterior DMN. At the same time, there was decreased activation of the Higher Visual Network during local attention processing. Variations in trait fear of missing out (FoMO) moderated the relationship between precuneus engagement and behavioral accuracy during local attention processing specifically during SD. Findings suggest that – compared to non-social media distraction - social online media information disrupts attention via the posterior DMN and stronger engagement of the higher visual cortex. Overall, this study provides valuable insights into the potential attention consequences of online social information intrusion and the neural mechanism underlying local attention disturbance in individuals with elevated levels of trait FoMO.