There is disclosed in one example a computing apparatus, including: a processor and a memory; instructions encoded within the memory to instruct the processor to: identify a downloaded file on a file system; inspect a metadata object attached to the downloaded file; parse the metadata object to extract an advertiser identification string from a GET code portion of a uniform resource locator (URL); query a reputation cache for a reputation for the advertiser identification string; receive a deceptive reputation for the advertiser identification string; and take a remedial action against the downloaded file.