Cyware Social
will be sunset on April 15, 2026. The service is being replaced by
Cyware's Daily Threat Intel Briefs,
offering curated security advisories on the latest threats. Enterprise users can contact us
here → for more details.
An array of cyber attacks on a Middle Eastern telecom company has indicated the return of the OilRig APT.
What’s happening?
The RDAT tool utilizes email as a Command and Control (C&C) channel, with attachments that conceal commands and data inside bitmap images through the use of steganography. The backdoor made its debut as a proprietary OilRig weapon three years back and has seen quite a lot of improvements throughout the years.
Latest attacks involving steganography
An email spam campaign was uncovered in the month of June that was spreading a new strain of the IcedID trojan. It exhibited various sophistication layers, such as steganography, HTTPs, and MSI.
In May, a targeted barrage of attacks on ICS suppliers was conducted through phishing and steganography.
Earlier this year, threat actors adopted steganography-based credit card skimmer to steal payment card details.
What’s different about this attack?
Unlike previous RDAT samples, this one uses only DNS tunneling for its C&C communications without any HTTP fallback channel.
Two email addresses are used by the RDAT payload to receive and send emails to facilitate C&C communications.
The method of data exfiltration is also the same as that used for hiding its C&C commands.
The bottom line
The OilRig APT has been using the unique RDAT backdoor since 2017 to attack organizations based in the Middle East. The use of a novel C&C channel, along with steganography, demonstrates that over time, the threat actors have put continual efforts into the development and evolution of their tactics and techniques.