Selective Disclosure Raises Questions

Opinion: Why would a researcher hold back with Microsoft vulnerabilities and disclose away with others?

A couple weeks ago we had a slightly odd report of a vulnerability in Internet Explorer.

It was perfectly plausible, and Microsoft as much as confirmed it by not denying it. The original research report claimed that fully patched Windows XP SP2 systems could be exploited through Internet Explorer 6.

It was noteworthy that the researcher, Tom Ferris, let out enough information to make the problem sound dire, including a screenshot of the program crash involved with the vulnerability, but no actual details of the vulnerability itself.

He even redacted the module name and offset in the screenshot to make it harder for third parties to work on the problem. There was no proof of concept provided, and it Ferris himself said he is unsure whether it can be exploited to execute arbitrary code, but he thinks it can.

This morning, when Ferris released another vulnerability report, I immediately recognized his name. This one affected the Firefox browser, including the current release level 1.0.6 and the newly released beta 1.5.

The report didnt hold back on details, or at least it didnt seem to. It even identified the exact object and method in the Firefox source where the problem lies, and Ferris provided instructions for exploiting it and a sample Web page to demonstrate.

There are still some funny aspects of this bug; it resembles a much older bug in Firefox that was supposed to have been fixed. Since current versions are clearly affected, perhaps the bug was reintroduced in later versions. In the meantime, one workaround is to set network.enableIDN to false in about:config.

So why did Ferris provide all the gory detail about Firefox but shelter us from it with the Internet Explorer bug? I asked online where he reported the bug and got no answer. I did get some lip from people who wanted it clear that disclosure was the right way.

Personally, Im not so sure. Id say that if the vulnerability is as serious as Ferris says it is, he was right to withhold details from the public before a patch was made available.

But releasing the kind of partial "I didnt inhale" report that Ferris did on the Full-Disclosure list is dissatisfying. There was no point in the IE disclosure that he made other than to blow his own horn, and he could have waited until there was a patch to blow it. Perhaps he thought hed get more attention this way, and I guess he was right about that.

I could argue that a partial disclosure about Firefox would be pointless, since bug reports are usually available to the public. But the Mozilla development team does close off Bugzilla reports for unresolved security issues, and perhaps thats whats happened in this case, since nobody can find Ferriss report that he claims he filed. If they hid it for security purposes they blundered by leaving the old report out in the open, since its the same thing.

All things considered, it seems to me that Ferris has a double standard here and I dont get it. The right thing to do here would have been to keep his mouth shut until a patch was available and then go karma-whoring.

The other important conclusion is that someone should go through all the rest of the resolved security problems in Firefox to see if any of them have been resurrected in recent versions.

Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983. He can be reached at


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