Trustwave to escape 'death penalty' for SSL skeleton key
Moz likely to spare certificate-confession biz same fate as DigiNotar
Analysis Trustwave's admission that it issued a digital "skeleton key" that allowed an unnamed private biz to spy on SSL-encrypted connections within its corporate network has sparked a fiery debate about trust on the internet.
Trustwave, an SSL certificate authority, confessed to supplying a subordinate root certificate as part of an information security product that allowed a customer to monitor employees' web communications - even if the staffers relied on HTTPS. Trustwave said the man-in-the-middle (MitM) gear was designed both to be tamper-proof and to work only within its unnamed client's compound. Despite these precautions, Trustwave now admits that the whole approach was misconceived and would not be repeated. In addition, it revoked the offending certificate.
Trustwave came clean without the need for pressure beforehand. Even so its action have split security experts and prompted calls on Mozilla's Bugzilla security list to remove the Trustwave root certificate from Firefox.
Death sentence debate
Critics claimed that Trustwave had enabled its client to issue arbitrary SSL certificates for any domain - this is in violation of Mozilla's policy against "knowingly issuing certificates without the knowledge of the entities whose information is referenced in the certificates". Trustwave sold a certificate knowing that it would be used in man-in-the-middle eavesdropping of encrypted information, an insecure practice that it ought to have never used in the first place.
Researcher and privacy advocate Christopher Soghoian weighed into the debate on Mozilla's list with the case for the prosecution.
"Trustwave sold a certificate knowing that it would be used to perform active man-in-the-middle interception of HTTPS traffic," he wrote. "This is very very different than the usual argument that is used to justify 'legitimate' intermediate certificates: the corporate customer wants to generate lots of certs for internal servers that it owns.
"Regardless of the fact that Trustwave has since realized that this is not a good business practice to be engaged in, the damage is done."
Soghoian concluded: "With root certificate power comes great responsibility. Trustwave has abused this power and trust, and so the appropriate punishment here is death (of its root certificate)."
Those defending Trustwave suggested that other vendors probably used the same approach for so-called "data loss prevention" environments - systems that inspect information flowing through a network to prevent leaks of commercially sensitive data. It would be wrong to impose a death sentence on Trustwave as a certificate authority after it came clean and abandoned the MitM digital certificate technique, the counterargument goes.
"Personally, I think Trustwave should be commended for being the first CA [certificate authority] to come forward, admit to, and renounce this practice of issuing unrestricted 3rd-party sub-CAs," Marsh Ray, a researcher and software developer at two-factor authentication service PhoneFactor, wrote in the Mozilla debate.
"When I read Mozilla's policy, and the CA/B Forum baseline requirements, I see enough wiggle room in there that someone might plausibly claim that some agreed-upon scenarios for MitM certs was not prohibited by the agreement. In fact Geotrust was openly advertising a 'Georoot' product on their website until fairly recently.
"Those who are advocating Trustwave's removal from the list would seem to be of the belief that Trustwave was somehow alone in this practice. As I do not hold that belief, I think it would be a mistake to continue to threaten Trustwave and discourage other CAs from coming forward at this time."
Next page: Trustwave fights backs
Why was it even necessary?
As this was a single enterprise in control of the PCs, it could have just pushed out it's own trusted root to the machines and installed them on other devices and accomplished exactly the same thing.
The average user wouldn't have been likely to know (if that's what they wanted).
They wouldn't then have needed the expense of using Trustwave.
They would only need a known Trusted Root Authority if they were also spying on visitors or guests using their network (public WiFi?). Which would raise a few more questions...
On Allocation of Blame
The problem here is that the people who are inconvenienced are the users of any site with a trustwave certificate. They will note that the website they want to visit appears 'broken' in Mozilla's browser, but fine for everyone else.
They then ditch whatever Mozilla product they were using and presumably switch to Chrome instead. End result? Mozilla's market share drops, the value of their 'SSL Death Penalty' drops, and Trustwave is only mildly inconvenienced.
Thus, unless there is a clear and present danger there is minimal benefit for Mozilla making a unilateral decision to blacklist a CA. This is one of those exciting emergent problems which SSL's developers almost certainly never thought of.
This sort of thing happened to us a few weeks ago ... firewall/security servers started to act as "man-in-middle" on https transaction for "virus/threat checking" with security certificates pointing to the server rather than the real site being accessed. The relevant certificate had already been pushed out to PCs so people using the "corporate IT standards" (i.e. IE) didn't notice but those of use using firefox (and, perish the thought, people using Unix machines) saw warnings of mismatching security certificates. Rapid and juge uproar followed - especially as people in French part of company pointed out that this was probably an illegale wire-tap under French law - and the system was dropped (allegedly for "performance reasons")