The UK's privacy watchdog has opened a tentative probe into the alleged security shortcomings of Tesco's website.
The global supermarket behemoth, which sends out password reminders to Tesco.com customers in plaintext, was accused by security researcher Troy Hunt of storing punters' credentials in an unsafe manner, as reported by El Reg several weeks ago.
Tesco has yet to respond in detail to Hunt's criticisms, but the chain defended its security as "robust" in a statement.
"We know how important internet security is to customers and the measures we have are robust," the firm argued. "We are never complacent and work continuously to give customers the confidence they can shop securely."
When a customer forgets his or her login credentials, Tesco emails the customer's actual password in clear text as a reminder, rather than following the more robust practice of reseting the account's records.
The retail giant insists it "secures" stored passwords, but its approach implies that the encryption used, if any is used at all, is two-way, allowing the original passphrases to be recovered. The argument goes that if Tesco's software can recover exact passwords from the database, so can hackers who penetrate the supermarket's systems.
Ideally, web apps should encrypt passwords using a one-way function, a technique known as hashing, that does not store the original passwords and frustrates efforts to recover plaintext credentials by hackers.
No database breach has occurred at Tesco.com, so Hunt's criticism centres on charges that the company is failing to follow best practices for password storage, failing to prevent cross-site scripting attacks and is mixing up encrypted and unencrypted content on a secure page.
Many readers have emailed us about Hunt's blog and the majority of security experts agree he has a point. However one or two dissenters have noted that Tesco's alleged password security malpractices are fairly common among huge corporations, so singling it out for particular blame appears somewhat unfair.
As previously noted, the password reminder issue on Tesco's website was first reported five years ago.
However, the UK's Information Commissioner's Office (ICO) confirmed this week that it is looking into the matter, but declined to comment further.
“We are aware of the issues relating to the Tesco website and will be making enquiries,” the ICO said in a statement. ®