Messaging security vendor CloudMark is leading calls for a clampdown on firms that deliberately target SMS spam at people with bad credit.
The company makes software that is used by internet service providers, including Virgin Media and BT, to protect their customers from spam emails, phishing attacks and viruses, for example.
Effectively, your details get sold on ad infinitum and they end up on the lists of these spammers.
During the summer months, the company claims to have seen a marked rise in the number of messages that fall under the "product information spam" category advertising smartphone and mobile contracts deals.
Speaking to IT Pro, Neil Cook, chief technology officer at CloudMark, said these types of messages are often targeted at people with bad credit, which he described as a "disturbing" trend.
"They often do target the vulnerable people in society, because they're not [aiming] this at people who are on a 50 a month contract with Vodafone," he explained.
"They're targeting people [with phrases like] 'if you've been refused a mobile phone contract before we'll try to get one for you'. It's definitely a concern."
He said these types of individuals usually end up on the spammers' radar because they've responded to messages of a similar nature before, or have been "inadvertently" signed up when their details have been sold or passed on to a third party.
"Effectively, your details get sold on ad infinitum and they end up on the lists of these spammers," he said.
In a similar vein, Cook said around 40-50 per cent of the spam reports his company receives are associated with payday loans, although this has dipped a little since the start of the summer.
This is a trend Cook has attributed to the recent clampdown on payday loan providers by the Office of Fair Trading, which has already prompted several firms to exit the market.
"If you look at compared to the beginning of the summer, it's slightly down, but it's still 40-50 per cent of the spam reports we see which, if you were the governor of the Bank of England, wouldn't make you terribly confident [about the UK's economic prospects]," he added.
Cook is quick to point out though, it's rarely mobile operators, phone manufacturers and payday loan firms that are directly responsible for these messages being sent out.
Instead, they're usually the work of affiliates who make money every time someone clicks on a link contained in the message.
"We often see affiliate programmes continue even...though the company they are working with, which often is a legitimate firm, is disavowing their practices," he explained.
"But on the back end these companies are quite disjointed so that there affiliate programme is [quite removed] from their own marketing activities."
Consumer watchdogs are getting tougher on companies that target society's more vulnerable types, he added, but it is a difficult area to clampdown on.
"We're trying to work with the industry to stop people getting this spam in the first place and to clean up the industry, and the networks. That's what our software does," he explained.
Educating users about the risks associated with responding to spam text messages only goes so far, he added, as there will always be people these types of missives appeal to.
"It's easy if you're, say, middle class and have no money worries don't click on these things, but to some people they might appear to be offering them a lifeline," Cook said.
However, those that don't want to receive any more of these types of messages can forward messages to the spam reporting service, 7726, which is then used by mobile operators to stop similar ones being sent to their subscribers in the future, he added.
