OTTAWA–Hundreds of federal employees’ email addresses are included in leaked membership data for hookup site Ashley Madison, released publicly by hackers who demanded the adultery-promoting service shut down.

The email addresses in no way confirm public servants’ participation on the site, nor do they indicate any wrongdoing — anyone could sign up someone else’s email address, and the site promoted single connections in addition to extra-marital affairs.

But the initial estimation of security researchers is the data does appear to be legitimate. And the mere presence of more than 500 federal government emails connected to the site raises a number of security concerns, both for government networks and for potential blackmail.

The emails were included among a massive leak of Ashley Madison users’ personal information, including credit card transactions, location data and sexual interests. The site boasts of almost 39 million users worldwide, but that number is probably inflated by fake, inactive or dummy accounts.

The federal Treasury Board, the department responsible for the government’s IT practices, directed queries Wednesday night to the government’s acceptable use policy: “The Guideline on Acceptable Network and Device Use applies to the professional and personal use of Government of Canada electronic networks and devices, and Web 2.0 tools and services, including social media,” wrote Rebecca Grace, acting director of the board’s public affairs department.

The information held by Ashley Madison’s owners, Avid Life Media Inc., is extremely sensitive. Security researchers and journalists have noted the hack, pulled off more than a month ago by a group calling themselves The Impact Team, is unique in its scope, sensitivity and potential for offline damage.

Ray Boisvert, a former assistant director of the Canadian Security Intelligence Service, said problems could arise if any of those employees had security clearances that could be exploited.

“Lifestyle is always a touchy issue because it’s not a judgmental thing (in security screening). . . . It’s really about the potential for compromise,” Boisvert said Wednesday.

“Why would you use your user name, your client ID, from your credentials from work, to log in and create an account at AshleyMadison.com? You’d think somebody would be using hotmail and, as most people do, a pseudonym.”

Boisvert said such credentials as email addresses or user names could be used by other malicious actors to try to gain access to other websites used by those people identified in the Ashley Madison hack.

In all, 548 unique email addresses for various federal agencies were included in the data dump, including Canadian Forces members, RCMP and Canadian Border Services employees.

A further 64 emails were connected to Toronto.ca.

A total of 1,494 emails with the Ontario.ca domain were included, but that domain covers everyone from school board employees to police to municipal staff.

The leak also includes emails with the domain names of prominent Canadian companies, including CP Rail, Scotiabank and CIBC, though it is impossible to verify if any of the email addresses are legitimate. Journalism outlets, including the Toronto Star, CBC, the Globe and Mail and CTV, appear among the emails.

When contacted Wednesday, CP Rail said it had no comment on the matter. The other companies and journalism outlets did not respond by press time.

The Star is not naming anyone included in the membership data, public employees or not. The data cannot be verified, and members are consenting adults.

In a statement Wednesday, Avid Life Media said it became aware of an attack on its systems in July and was actively investigating the hack. The Toronto-based company said it was co-operating with investigators from the RCMP, Ontario Provincial Police, the FBI, as well as the Toronto Police Service.

“This event is not an act of hacktivism, it is an act of criminality,” the company wrote. “It is an illegal action against the individual members of AshleyMadison.com, as well as any freethinking people who choose to engage in fully lawful online activities.”

The company’s slogan — “Life is short. Have an Affair” — apparently drew the ire of The Impact Team. In July, the group demanded Ashley Madison shut down within a month.

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“We have explained the fraud, deceit, and stupidity of (Avid Life Media) and their members. Now everyone gets to see their data,” the group posted in a statement accompanying the data.

“Find yourself in here? It was ALM that failed you and lied to you. Prosecute them and claim damages . . . Embarrassing now, but you’ll get over it.”

Although the site’s marketing focuses on extra-marital affairs, the service can also be used by single men and women for consensual relationships. The sites’ users appear to be predominantly male.