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The campaign, dubbed CostaRicto by BlackBerry, appears to be operated by “hackers-for-hire”, a group of APT mercenaries who possess bespoke malware tooling and complex VPN proxy and SSH tunneling capabilities.

Their tactics, techniques, and procedures (TTPs) often resemble highly sophisticated state-sponsored campaigns, but the profiles and geography of their victims are far too diverse to be aligned with a single bad actor’s interests.

Key Findings  from the report:

  • CostaRicto targets are scattered across different countries in Europe, Americas, Asia, Australia and Africa, but the biggest concentration appears to be in South Asia (especially India, Bangladesh and Singapore), suggesting that the threat actor could be based in that region, but working on a wide range of commissions from diverse clients.
  • The command-and-control (C2) servers are managed via Tor and/or through a layer of proxies; a complex network of SSH tunnels are also established in the victim’s environment. These practices reveal better-than-average operation security.
  • The backdoor used as a foothold is a new strain of never-before-seen malware – a custom-built tool with a suggestive project name, well-structured code, and detailed versioning system. The earliest timestamps are from October 2019, and based on the version numbers, the project appears to be in the debug testing phase. It’s not clear as of now if it’s something that the threat actors developed in-house or obtained for exclusive use as part of beta testing from another entity.
  • The timestamps of payload stagers go back to 2017, which might suggest the operation itself has been going on for a while, but used to deliver a different payload. It’s not impossible, though, that the stagers are simply being reused without recompilation (i.e.: by changing the C2 URLs via binary editing).
  • Some of the domain names hardcoded in the backdoor binaries seem to spoof legitimate domains (e.g.: the malicious domain sbibd[.]net spoofing a legitimate domain of the State Bank of India Bangladesh, sbibd.com). However, victims affected by these backdoors are unrelated, suggesting reuse of existing infrastructure which served another purpose.

  • One of the IP addresses which the backdoor domains were registered to overlaps with an earlier phishing campaign attributed to APT28 However, BlackBerry researchers r believe that a direct link between CostaRicto and APT28 is highly unlikely. It might be  coincidental, or –  the earlier phishing campaigns have been outsourced to the mercenary on behalf of the actual threat actor.

You can find the detailed report here: https://blogs.blackberry.com/en/2020/11/the-costaricto-campaign-cyber-espionage-outsourced