The resumés of thousands vying to get jobs as mercenaries with TigerSwan, a North Carolina-based private security firm, have been found exposed to public gaze on the Internet.

The material was found in a cloud-based repository by the Cyber Risk Team at Upguard, a security firm which has found many such unsecured caches of data in the past.

The sensitive personal details of the job applicants, many claiming top-secret security clearance from the US government, were left unsecured by a recruiting company with whom TigerSwan had cut ties in February 2017, according to UpGuard.

Most of the data belongs to US military veterans and exposed details about their past duties, which included elite or sensitive defence and intelligence roles.

Apart from routine information such as addresses and phone numbers, the CVs also listed security clearances, drivers' licence numbers, passport numbers and at least partial US Social Security numbers.

A sample resumé from the stash with data redacted. Courtesy UpGuard

UpGuard said in addition there were resumés from Iraqis and Afghans who had co-operated with US forces, contractors and government agencies in their home countries and who could be endangered by the disclosure of such details.

The document stash was found by UpGuard's director of Cyber risk research Chris Viceroy on 20 July, in an Amazon Web Services S3 storage bucket configured for public access – as has been the case with some previous discoveries.

It was located at the AWS subdomain "tigerswanresumes" and TigerSwan was notified the following day by email and again by both phone and email on 22 July. But the files were not secured until 24 August.

Describing the find, UpGuard's Dan O'Sullivan wrote: "A cursory examination of some of the exposed resumes indicates not merely the varied and elite calibre of many of the applicants as experienced intelligence and military figures, but sensitive, identifying personal details. Applicant names, home addresses, phone numbers, email addresses, and driver’s license numbers are exposed throughout."

There were numerous others whose details were exposed: for example, a former UN worker in the Middle East, a parliamentary security office from Eastern Europe, an active Secret Service agent, a Central African logistical expert, an ex-soldier tasked with providing security in war zones for TV news crews and a police chief in a southern state.

O'Sullivan wrote: "The battlegrounds of Iraq and Afghanistan recur throughout the repository, with 3669 and 2712 resumés mentioning each, respectively.

"A sizeable number of these resumés mention service in these two flashpoints not just as US soldiers, but from other Coalition and NATO member states like Canada and the UK, as well as through private military contractors like DynCorp, Blackwater, Aegis, Kellogg Brown Root, Lockheed Martin, and Titan, among others."

Additionally, the contact information of a former US ambassador to Indonesia and a former director of the CIA's clandestine service were listed among the references in a resumé.

"The potential utility of the repository that was left unsecured here is multivaried. While criminals could use the deep knowledge of work experience and personal details for anything from identity theft to one of the phishing scams known to specifically target veterans, the value of this database to foreign intelligence agencies if they were to access it is not insignificant," O'Sullivan wrote.

"The presence of extremist sympathisers in Western nations makes the prospect of publicly exposed Iraqi and Afghan nationals that much more alarming. Given these risks, the month-long delay from when TigerSwan was notified about the exposure and the data ultimately being secured is especially unfortunate. A strong cyber resilience programme should include the ability to respond quickly and with agility when exposure of sensitive information is discovered."