Turla Espionage Group, infamous for targeting governments, their officials and diplomats since at least 2007, has added a new campaign to its arsenal. According to ESET, the latest watering hole tactic includes updated Firefox Extension abusing the popular social network – Instagram.
As usual, Turla’s watering hole attacks compromise websites that are likely to be visited by their targets of interest in order to redirect them to their Command and Control (C&C) infrastructure. When monitoring recent campaigns, ESET reserachers spotted a previously documented Firefox extension dropped. Unlike the previous version, the extension uses a bit.ly URL to reach its C&C. However, the URL path is nowhere to be found in the Firefox extensions, but instead obtained by using comments posted on a specific Instagram post. An analysed example was a post made on Britney Spears Instagram account.
To obtain the bit.ly URL, the extension screens each photo’s comments, for each comment it computes it has a custom hash value. If the hash value matches the number, it will then run the regular expression on the comment in order to obtain the URL path.
“The fact that Turla is using social media to recover C&C addresses is making life harder for cybersecurity vendors as the tactic makes it difficult to distinguish malicious traffic from legitimate traffic to social media,” explains Jean-Ian Boutin, Senior Malware Reseracher at ESET. “As the information needed to obtain the command and control URL is simply a comment on social media, the attacker has the possibility to easily modify it or completely erase it.”
To avoid being drawn into such watering hole campaign, ESET reserachers recommend as a good practice – keeping browsers and browsers’ plugins up-to-date. Another principle worth adopting is to avoid downloading and installing any extensions/add-ons coming from illegitimate sources. Luckily, modern cybersecurity solutions are able to detect suspicious looking websites and warn users, so it is always good to have one active and up to date.