The DreamBus botnet has resurfaced after a two-year break and it has been seen exploiting a recently patched Apache RocketMQ vulnerability in attacks whose goal is the delivery of a cryptocurrency miner.
Apache RocketMQ is a widely used distributed messaging and streaming platform. The exploited vulnerability is tracked as CVE-2023-33246 and its existence came to light in late May, when RocketMQ version 5.1.1 was released to patch the issue.
CVE-2023-33246 has been classified as ‘critical’ and it can be exploited by an unauthenticated attacker for remote command execution.
Details and proof-of-concept (PoC) exploits emerged in June, and reports of exploitation in the wild emerged shortly after. The ZoomEye cyberspace mapping service had recorded more than 6,000 traces of intrusion at the time — mainly in China — and the number has now gone up to 11,000.
Juniper Networks reported this week that it started seeing attacks exploiting CVE-2023-33246 in early June, with a peak reached in mid-June, as part of activity associated with the DreamBus botnet.
The first exploitation attempts were designed to look for vulnerable RocketMQ servers, but threat actors later started delivering a malicious bash script designed to download the main module of the DreamBus malware.
This main module, which is an ELF Linux binary, has been packed with the UPX executable file compressor but in a way that makes the malware’s analysis more difficult.
DreamBus is a Linux malware that emerged in early 2019, but Juniper said it had not been seen since 2021, until now.
The main goal in this case appears to be the distribution of a Monero cryptocurrency miner on infected systems. However, Juniper researchers said DreamBus can also attempt to spread to internal and external IP ranges. This worm-like behavior is not new for the malware.
“As DreamBus malicious threat actors resurface, their primary objective remains the installation of a Monero cryptocurrency miner. However, the presence of a modular bot like the DreamBus malware equipped with the ability to execute bash scripts provides these cybercriminals the potential to diversify their attack repertoire, including the installation of various other forms of malware,” Juniper said.
Juniper provides indicators of compromise (IoCs) and recommendations for protecting systems against such attacks.
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