Apologies if this is too off-topic. This seemed like the closest-fit SE site for this

A lot of people will have at some point received a spam text offering some sort of help via a debt settlement order, or help claiming for an accident that they have never had. I’ve noticed these are prevalent in both the US and UK, and expect other nationals will have similar stories. For those that haven’t, you receive a text message out of the blue from a seemingly ‘personal’ number, and are then encouraged to “text YES if you’re interested, or NO to stop”. It’s clearly a sham, but some people are inevitably drawn in.

After receiving one myself, I blogged about it (warning people not to reply), and within a month it was getting 1000+ hot and 50+ comments per day (staggering for a small independent blogger like me) – most respondents posting different originating numbers.

I’m keen on doing a follow up story, so, really, my broad question is, how on earth do they work? What I know is based on a lot of guesswork and assumptions, and may be wildly erroneous so something more concrete would be marvellous.

As far as I can tell, when you reply to a message it gets added to a database somewhere, and the record is sold to a company offering that line of business.

My research has lead me to one company (leadex.com – [deliberately unlinked]) that appear to specialise in this sort of harvesting. I’m guessing that their clients have some sort of online alert configured, upon which their operatives can then take action (i.e. call the number). Moreover, I’ve encountered some projects on freelancer.com, posted by people/companies that seem to want this sort of infrastructure set up (click for example project)

I’ve also come to understand that it’s possible the messages themselves are being sent from a single source, which is itself spoofing the numbers to ones that the company is able to monitor. Respondents to the article have also reported that when they call the number it goes through to a standard network provider voice mailbox.

But, I’m still not entirely sure. Can anyone help?

  • What sort of equipment, infrastructure, software, etc will they require?
  • How are they able to obtain such large batches of numbers – do the network operators sell them in this way?
  • Given that they these ‘batches’ of numbers, so how are they able to setup and monitor them (is everything redirected to a single source).
  • How permanent/transient is this setup? I.e. are numbers only ‘Live’ for a short period of time.

And absolutely anything else, which might be of relevance/interest

I’ll be linking back to this question from the post, and including any relevant links that people include as well – happy to link to personal blogs as well.

  • 2
    I think this is a good fit and I look forward to seeing any answers.
    – C. Ross
    Mar 7, 2011 at 14:49

1 Answer 1


There are likely to be two approaches:

  1. Number-generator: interested in collecting valid telephone numbers for onward sale;
  2. Service generator: interested in contacting the end-user for selling them something (either directly or as an intermediary);

An autodialer of any description would be more than capable of sending an SMS or initiating a direct telephone call with any set of telephone numbers. Such autodialiers can run off a personal computer via VoIP or some such third-party. As to getting the numbers, it can be either from a purchased list (if they're serious about this and are obeying any call opt-out lists) or simply a number range dialed sequentially, whether they work or not.

In a more serious operation, any returns are fed directly to a call centre where real human beings then initiate direct contact. Otherwise it is simply a fishing expedition and any valid numbers can then be sold to other agencies as a screened list (and, therefore, more valuable).

From an SMS perspective, anyone can purchase a vendor-level SMS Gateway subscription (of which there are loads of vendors - and note the number that allow "web-to-SMS") which permits you to receive and respond to any SMS received.

This is always about the "law of large numbers". If they can get in the hundreds of thousands of valid numbers and a small number respond then they can make money. Like any spam, because a few are gullible, the rest of us are targets too.


A few searches for "software auto sms" and similar results in a fair number of prospects. As I don't wish this to become too much of a "how-to" I'm not going to link.

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