The budget deal that you heard about yesterday isn't exactly what you might think it is. The process is supposed to work like this. First a budget is passed. The budget merely sets top line numbers for the total amount to be spent and for each separate appropriations bill. It's the actual appropriations bills that give agencies money to spend. Budget summaries often say how much individual agencies are to get but these summaries are merely recommendations.
Passing appropriations bills is tough in this political environment. Social Security's appropriation, or Limitation on Administrative Expenditures (LAE) as it's officially known, is part of the Labor-HHS appropriations bill. The Labor-HHS appropriations bill is always the most contentious of the appropriations bills, particularly now since Republicans are still trying to find a way to use the appropriations process to hobble the Affordable Care Act. If the hobbling can be done, it would be done through the Labor-HHS appropriations bill.
Passage of the budget deal announced yesterday is itself no slam dunk. House Democrats had earlier said they would not vote for the deal unless it included an extension for Unemployment Insurance benefits set to expire this month and this deal doesn't do that. Some Republican members of the House had announced that they would not vote for the deal because they thought that the budget was set too high. If all of the House Democrats and all the dissenting Republicans vote against this budget bill, it will fail in the House of Representatives and we're back to square one.
Despite the budget deal announced yesterday, there's a real risk of a government shutdown in January either because the budget deal itself can't be passed or because appropriations bills can't be passed.