From a summary of a report by Social Security's Office of Inspector General:
Our Office of Investigations (OI) has received several allegations concerning SSA employees who issued fraudulent SSI [Supplemental Security Income] underpayments. As of May 2014, OI had investigated 10 allegations, which led to the conviction of 9 former employees for wrongdoing and resulted in incarceration and/or restitution to SSA[Social Security Administration] . ...
Using targeted data analysis, we identified several SSA employees who may have inappropriately processed large numbers and/or high dollar amounts of SSI underpayments. We sent two cases to OI for further analysis. As of the date of this review, OI was investigating both cases. We sent the remaining outlier transactions, including 35 Social Security and 57 employee personal identification numbers, to SSA for further analysis. SSA could not locate documentation and notices to support underpayments and stated employees did not always follow SSI underpayment policies and procedures. SSA representatives stated the Agency would take a number of actions to address these employee errors, including providing employees additional training. ...After the Eric Conn case blew up, Social Security became even more concerned about fraud than it had been. A lot of money was spent on software to identify big fraud cases. It turns out they haven't been finding much in the way of fraud committed by claimants apart from the routine individual stuff --disability claimants concealing that they had returned to work, for instance -- but they do seem to have been finding more employee fraud. It's still nickel and dime stuff though in the big picture.