Target hackers may have exploited backdoor in widely used server software

Widely used management software running on Target’s internal network may have given an important leg up to attackers who compromised 40 million payment cards belonging to people who recently shopped at the retail giant, according to an article published Wednesday by KrebsonSecurity.

As journalist Brian Krebs reported two weeks ago, malware that infected Target’s point-of-sale terminals used the account name “Best1_user” and the password “BackupU$r” to log in to a control server inside the Target network. The malware used the privileged insider access to temporarily stash payment card data siphoned out of the terminals used in checkout lines so it could then periodically be downloaded to a different service for permanent storage. In Wednesday’s post, Krebs filled in some intriguing new details that suggest a poorly secured feature inside a widely used server management program may have played a role. Krebs explained:

That “Best1_user” account name seems an odd one for the attackers to have picked at random, but there is a better explanation: That username is the same one that gets installed with an IT management software suite called Performance Assurance for Microsoft Servers. This product, according to its maker — Houston, Texas based BMC Software — includes administrator-level user account called “Best1_user.”

This knowledge base article (PDF) published by BMC explains the Best1_user account is used by the software to do routine tasks. That article states that while the Best1_user account is essentially a “system” or “administrator” level account on the host machine, customers shouldn’t concern themselves with this account because “it is not a member of any group (not even the ‘users’ group) and therefore can’t be used to login to the system.”

“The only privilege that the account is granted is the ability to run as a batch job,” the document states, indicating that it could be used to run programs if invoked from a command prompt.

Krebs went on to quote a part of the BMC article that said:

Read 3 remaining paragraphs | Comments


via Ars Technica


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