Pierluigi Paganini August 03, 2019

Researchers at Proofpoint discovered SystemBC, a new strain of proxy malware that is being distributed via Fallout and RIG Exploit Kits

A new piece of malware dubbed SystemBC was discovered by experts at Proofpoint, it is being distributed via exploit kits like Fallout and RIG. The malware was tracked as “SystemBC” based on the URI path shown in the advertisement’s panel screenshots.

The malware hides malicious network traffic using SOCKS5 proxies that set up on compromised PCs.

The use of SOCKS5 proxies was observed several times by malware researchers, it allows to avoid detection bypassing security measures that identify malicious traffic. SOCKS5 proxies also allow hiding Command & Control servers making takedowns. SystemBC communicates with C2 server via HTTPs connections.

“SystemBC is a previously undocumented malware that we have recently observed as a payload in both RIG and Fallout exploit kit (EK) campaigns.” states the analysis published by Proofpoint.

“SystemBC is written in C++ and primarily sets up SOCKS5 proxies on victim computers that can then be used by threat actors to tunnel/hide the malicious traffic associated with other malware,”

The most recently analyzed sample of SystemBC uses the Fallout Exploit to deliver the Danabot banking Trojan.

SystemBC malware was also detected by other researchers like the popular exper Vitali Kramez:

The experts spotted a variant of the SystemBC proxy malware while analyzing a Fallout EK campaign on June 4, 2019 that was deliveriing the Danabot banking Trojan. Other campaigns were monitored by the experts during June and July.

Another campaign from June 6 was dropping a PowerEnum PowerShell script that threat actors use for device fingerprinting and data exfiltration.

In July, experts discovered a new sample of the SystemBC proxy malware that was being distributed by the Amadey Loader, which itself was being distributed in a RIG EK campaign.

“Since this proxy malware was being used in multiple separate campaigns, Proofpoint researchers believe it was very likely that it was being sold in an underground marketplace.” continues the analysis. “Moreover, we found an advertisement from April 2, 2019, on an underground forum that described a malware named “socks5 backconnect system” that matched the functionality of the malware seen in the above campaigns.”

Researchers at Proofpoint believe that the proxy malware is available for sale via an underground marketplace, an advertisement on a Russian crime forum promotes a malware called “socks5 backconnect system” that appears to be SystemBC.

“The synergy between SystemBC as a malicious proxy and mainstream malware creates new challenges for defenders relying on network edge detections to intercept and mitigate threats like banking Trojans.” concludes the report that also includes IoCs and other details.

Pierluigi Paganini

(SecurityAffairs – SystemBC malware, hacking)

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