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Microsoft Flip-Flops On URI Protocol Handing Flaw
a-twitter writes "After months of insisting there is nothing to patch, Microsoft has done a complete 180 on the URI protocol handling vulnerability, announcing in a security advisory that a Windows update will be released to revise URI handling code within ShellExecute() to be more strict. The MSRC blog explains the background and offers more details on this issue."
You're not paying attention. There were two flaws: One in Firefox, one in ShellExecute. Microsoft cannot and did not fix the flaw in Firefox (incorrect interpretation of command line). Microsoft did fix the bug in ShellExecute, which was by the failure to abort if URLMON returned an error code indicating that a given string was not a legal URI.
Well, actually, there are two issues being mentioned here. One, where Windows itself mishandles the URI. This is the one where a % symbol is included in the URI and ShellExecute stupidly tries to fix it (demons know how it manages to mangle it into an actual working executable path). The other, which Microsoft correctly attributes to third party vendors, is where when a protocol handler is called, no escaping of quotes is done - often causing apps like Firefox, or Trillian, or whatever, to actually accept half the URI as command line parameters.
The mistake made by the GP (and potentially yourself, as you refer to the "blame cast" with the Firefox team which from memory only occurred with the issue in June with a malicious URIs terminating the quoted string and including Chrome parameters) is that they assume the second option is the one which is being fixed. It is not. This will potentially still be a problem if applications don't continue to validate their URIs appropriately, as Windows doesn't know exactly what your application does to escape quotes.
One of these is a vulnerability. The other is third party applications violating a basic tenet of development (no input is trusted).
For a site about things like basic rights, Slashdot users sure do like to censor "dissent".
There are two "bugs" being talked about.
1) an exploit in firefox URI protocol handler
2) an exploit related to how explorer handles rejected URIs from IE7 on XP/Win2k3
Apparently the submitter isn't able to differentiate #2 from #1.
The advisory is for item #2. Item #2 is going to get fixed. The advisory does not cover item #1. Item #1 will need to be fixed in the protocol handler itself.