WithoutFire | John Elliott's occasional thoughts on data protection

An analysis of the T-Mobile breach

There’s been a lot in the press for the past few days about the recent T-Mobile breach. Basically it appears that a number of staff at the mobile phone company have been selling customer data which included the customer’s name, their mobile number and when their contract expired. There hasn’t been a great deal of information about this other than the BBC’s report, the Information Comissioner’s press release (PDF) and a short post on T-Mobile’s customer support forum.

From an information security and Data Protection Act compliance perspective there are three breaches of the Act.


There’s no information how the data was extracted from T-Mobile’s system and I accept that it could have been by people copying the information down onto pieces of paper, however I’ll assume that as the BBC story talked about “millions of records from thousands of customers”, there was a bulk extract of data.

T-Mobile is probably in breach of the seventh principle in that they failed to ensure:

“Appropriate technical and organisational measures shall be taken against unauthorised or unlawful processing of personal data”

It is a breach of section 4(4) of the Act if a data controller fails to comply with the data protection principles in relation to all personal data, and the Information Commissioner (for the moment) can commence enforcement proceedings against the company, in the course of which T-Mobile will have to undertake to implement better security and processes.

However what’s interesting to me is whether T-Mobile had ever properly quantified the commercial value of information about a customer’s name, mobile and contract expiration date? And if so whether this was adequately reflected in their risk analysis?

If this were the case then two technical steps I’d expect them to have taken would have been:

  1. to make it very hard for people to run and save a report that had more than (say) 20 such records (most people working in customer service wouldn’t even need this many records in a report)
  2. to implement some Data Leakage Prevention (DLP) technology that looked at the type of data moving out of the organisation in email, on removable media such as CDs, USB sticks and as physical printouts

The employee / employees

The employee(s) [the T-Mobile site now appears to indicate that it was just the action of a single employee] have committed a clear offence under Section 55(1) of the Act.

“A person must not knowingly or recklessly, without the consent of the data controller obtain or disclose personal data or the information contained in personal data”

If convicted they’ll receive a maximum of a £5,000 fine (and if the Information Commissioner gets his way then next year this could be a custodial sentence).

The data recipient

The person buying the data has also committed a Section 55 offence as they obtained the data without T-Mobile’s consent.

The identity of the person or company who purchased the data hasn’t been made public. It will be interesting to see whether it was a small phone dealer, a broker or one of the other big mobile phone companies. If the latter the there’s a real issue to explore – was this the action of a ‘rogue’ salesperson or something that was tacitly condoned by the organisation?

For a market to exist in personal data there has to be both a buyer and a seller, and the value of the data is defined by the buyer: if no one wanted to buy this information then the T-Mobile employee(s) wouldn’t have stolen it to sell. If the data was traded through a list broker then still the recipient organisation should have asked themselves where this data came from as alongside the section 55 offence they will have breached the first (be fair when you get, use and share data) and second (tell people what you will do with their data, do nothing more) data protection principles.

When this case finally comes to court I’ll be really interested to see the action taken against the purchasers of the personal data.

In the future I expect to see all databases that hold personal information equipped with full read auditing which would create an audit log entry whenever a user read an individual record, or ran a report that included that record.

Audit: User JohnDoe viewed this record at 10:23 on 22/10/09<br></br>
Audit: User JaneDoe included this record in the report <em>CustomersAboutToLeave</em> at 19:47 on 23/10/09```

I’d also expect mobile phone companies to correlate the read activity of their users (recorded in this type of audit log) against the customers who went elsewhere at the end of their contracts.

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