Superfish flaw

Researchers uncover signs of Superfish-style attacks

lenovo
Credit: TAKA@P.P.R.S

EFF duo find clues of possible attacks against visitors to Amazon, Google, Yahoo, Wells Fargo and other websites

Researchers at the Electronic Frontier Foundation (EFF) yesterday said that they had found evidence that implies attackers have exploited a security vulnerability in the Superfish adware and a slew of other programs.

Superfish, a company that markets a visual search product, made the news last week when Lenovo was found to have pre-loaded the program on its consumer-grade PCs during a four-month span late last year. Lenovo has acknowledged that Superfish poses a security threat to customers, and has released a tool to eradicate the software.

Microsoft, McAfee -- both Lenovo partners -- and Symantec have also issued anti-malware updates that scrub Superfish from PCs.

But the problem extends beyond Superfish, security experts have discovered. Other programs also rely on the same code library -- one created by Israeli company Komodia -- to circumvent Web encryption with a proxy.

Because of the way Komodia's proxy works, the security implications are much more dire than initially thought, when researchers focused only on the weak password used by Superfish's self-signed certificate. The proxy does not properly validate certificates, letting attackers create totally bogus certificates of their own to mimic legitimate ones used by websites, including those of banks' online access.

By hijacking a Web session -- the most common way would be using a "man-in-the-middle" (MITM) attack over a public, insecure Wi-Fi network -- hackers could redirect traffic to their own fake websites ... and the victim's browser would put up neither a warning nor a fuss.

"This means that whoever has Komodia software running on their system will accept ANY certificate that has the domain name in the [Alternate Names field of the certificate]," said Filippo Valsorda of security firm CloudFlare in a Feb. 20 post to his personal blog. "No need to extract root keys from each software, this allows MITM [attacks] against all Komodia-using software at the same time. It's catastrophic."

EFF found evidence of just such attacks, reported Joseph Bonneau, a technical fellow with the organization, and Jeremy Gillula, a staff technologist. Bonneau is also a post-doctoral researcher with Stanford University's Applied Cryptography Group.

Ars Technica reported on the EFF's findings late Wednesday.

The digital rights advocacy group mined the data in its Decentralized SSL Observatory -- which was launched in 2011 as an early-warning system for unauthorized or compromised encryption certificates -- and found 1,600 entries representing certificates that Komodia should have rejected but did not.

Some of those certificates were for major Web destinations, including Amazon, eBay, Google, Microsoft's Outlook.com email service, Twitter and Yahoo. Bonneau and Gillula also found certificates of several banking sites, among them HSBC and Wells Fargo, and for Mint.com, Intuit's mobile personal finance program.

Bonneau and Gillula were careful in their conclusions, but decided that at least some of the 1,600 certificates they found were the result of in-the-wild attacks.

"While it's likely that some of these domains had legitimately invalid certificates, due to configuration errors or other routine issues, it seems unlikely that all of them did," the pair wrote. "Thus it's possible that Komodia's software enabled real MITM attacks which gave attackers access to people's email, search histories, social media accounts, e-commerce accounts, bank accounts, and even the ability to install malicious software that could permanently compromise a user's browser or read their encryption keys."

Bonneau and Gillula also tallied thousands of certificates linked to PrivDog, adware with ties to certificate-issuing security vendor Comodo. Like the Komodia proxy used in Superfish and other software, PrivDog blithely accepts rogue certificates that would normally trigger browser warnings.

"The Decentralized SSL Observatory has collected over 17,000 different certificates from PrivDog users, any one of which could be from an attack. Unfortunately, there's no way to know for sure," said Bonneau and Gillula.

Previously, security experts had called on Lenovo and other PC makers to halt the practice of factory-installing third-party programs -- called everything from "bloatware" to "crapware" -- because of potential security and privacy holes.

Bonneau and Gillula went a step further, urging computer buyers to reformat the machine's storage space and reinstall an OS from scratch. They also demanded that software developers stop intercepting encrypted HTTPS traffic, even for purportedly legitimate reasons.

"Taking certificate validation outside of the browser and attempting to design any piece of cryptographic software from scratch without painstaking security audits is a recipe for disaster," they argued.

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