Mozilla CTO Brendan Eich has cautioned netizens not to blindly trust software vendors, arguing that only open-source software can be assured to be free from government-mandated surveillance code.
"Every major browser today is distributed by an organization within reach of surveillance laws," Eich wrote in a joint blog post with Mozilla research and development VP Andreas Gal on Saturday.
Under those laws, Eich argued, governments could compel software companies to include surveillance code in their products. Worse, the vendors may not be able to admit to the public that such code exists when asked, because of gag orders.
The Mozilla man argued that open-source software can help alleviate this risk because customers have the opportunity to review its source code and spot any potential backdoors.
Equally important, Eich said, security researchers can compile open-source projects from source and compare the output to the executable binaries distributed by software vendors to make sure that the downloadable binaries don't include any undisclosed extras.
That's not possible for a product like Internet Explorer, Eich said, because Microsoft doesn't share any of its proprietary code with customers.
Even browsers that use open-source HTML rendering engines such as WebKit and Blink are not safe, he added, pointing out that both Safari and Chrome contain "significant fractions" of proprietary code, into which governments could potentially sink their hooks.
"Mozilla Firefox in contrast is 100 per cent open source," Eich wrote, by way of tooting the nonprofit's own horn.
Not that this fact has necessarily shielded Firefox users from surveillance so far. In August, a version of Firefox that was distributed for use with the anonymizing Tor network was found to be vulnerable to an exploit that could leak users' MAC addresses to attackers. Scammers have also occasionally tricked Firefox users into downloading fake, malware-laden updates.
To combat this, Eich has called upon security researchers to "regularly audit Mozilla source and verified builds by all effective means" – including establishing automated procedures – and to raise a public alarm if they discover any irregularities.
In turn, he proposed, such fully audited browsers could potentially be used as "trust anchors" to verify the authenticity of internet services, which could also contain secret surveillance code.
"Security is never 'done' – it is a process, not a final rest-state," Eich wrote. "No silver bullets. All methods have limits. However, open-source audibility cleanly beats the lack of ability to audit source vs. binary." ®