I just ran across a nasty worm in one of my WordPress blogs (not the most current install). Not only did it overwrite a ton of files, inserting spam links and malware into the pages, but it was sneaky enough to go into my wp-admin/.svn/prop-base/ directory and re-write those files as well. It’s fairly ingenious from the hacker standpoint. Most people like me will rely on the svn revert file.php to send the file back to its original version. That won’t work if the .svn/prop-base files are altered because svn will see that they are the same – it doesn’t bother actually checking the repo, so you’re stuck with infected files.
I solved my problem by deleting the wp-admin directory and doing an svn-up on its parent. That forces SVN to say “hey – that directory is missing. I should pull it down from the repository.” Problem solved (for now).
And I am now running the most current version of WordPress, so hopefully I’m free of risk and infection from here on out.