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By Max Gannon and Alan Rainer, Cofense IntelligenceTM

Threat actors continue to exploit legitimate services to trick users, as seen in the latest campaign using Raccoon Stealer malware, aimed at a financial organization and delivered by a Dropbox-hosted .IMG file. A rather unsophisticated malware, Raccoon Stealer came to light around April 2019, bypassing Symantec Email Security and Microsoft EOP gateways. The malware is sold on underground forums in both Russian and English, features an easy-to-use interface, around-the-clock customer support, and highly active development. Users of the malware can distribute it in any way they deem fit. In this campaign, the actors chose to host the malicious .IMG file on a Dropbox share, which upon execution, drops Raccoon Stealer onto the victim machine.

The email used in this campaign was delivered to the inbox of an employee of a financial institution. Figure 1 shows the email signature and originator address which probably belong to a compromised user. Using the familiar theme of a wire transfer—closely akin to those often seen in Business Email Compromise (BEC) scams—the threat actors look to trick users into opening the Dropbox URL and downloading the malicious file.

Educating users on spotting these types of scams and carefully scrutinizing emails that originate outside the organization are great ways to thwart this threat. Cofense IntelligenceTM Indicators of Compromise (IOCs) provided via our feed and noted in the appendix below can be used to fortify network defense and endpoint protection solutions.

Technical Findings

In the past, CofenseTM has seen Raccoon Stealer delivered by direct attachments and via RTF documents leveraging CVE-2017-8570 that targeted sectors such as utilities. In this most recent campaign, a potentially compromised email account was used to send the email shown in Figure 1, which managed to make its way past Symantec Email Security and Microsoft EOP gateways without the URL being removed or tampered with to the extent that it would prevent victims from clicking on it and downloading the payload.

Figure 1: Email delivering Dropbox URL

Raccoon Stealer is a relatively new malware that first appeared on the market around April 2019. Due to Raccoon Stealer’s ease of use and range of capabilities that allow for quick monetization of infected users, it is becoming increasingly popular. Although not particularly advanced or subtle with its network activity and processes, the malware can quickly gather and exfiltrate data as well as download additional payloads.

Initial contact with the command and control center (C2) is made when the malware does an HTTP POST that includes the “bot ID” and “configuration ID”. The C2 location responds with a JSON object explicitly including C2 data and payload locations for libraries and additional files, as shown in Figure 2.

Figure 2: Configuration Data From C2

The payload URLs currently deliver a set of DLLs, as specified by the “attachment url” and “libraries” parameters, but future development could easily allow threat actors to use Racoon Stealer as a loader for other malware to generate additional income.

The use of several distinct delivery methods in a relatively short time, including via the Fallout Exploit Kit, may indicate increased usage by numerous threat actors as predicted in prior Cofense research. Given the variety of delivery options, Racoon Stealer could be a problem for organizations that focus too much on one infection vector.

Table 1: Indicators of Compromise

Description

Indicator

Dropbox URL

hXXp://www[.]dropbox[.]com/s/g6pz8dm4051rs0o/SCAN%20DOC[.]IMG?dl=1

Raccoon Stealer C2 Locations

34[.]89[.]185[.]248

hXXp://34[.]89[.]185[.]248/file_handler/file[.]php hXXp://34[.]89[.]185[.]248/gate/libs[.]zip hXXp://34[.]89[.]185[.]248/gate/log[.]php hXXp://34[.]89[.]185[.]248/gate/sqlite3[.]dll

Raccoon Stealer Hashes

SCAN DOC.exe             f7bcb18e5814db9fd51d0ab05f2d7ee9

SCAN DOC.IMG            0c8158e2a4267eea51e12b6890e68da8

HOW COFENSE CAN HELP

Cofense PhishMeTM Offers a simulation template, “Dropbox Wire Transfer – Raccoon Stealer,” to educate users on the phishing tactic described in today’s blog.

Cofense IntelligenceTM: ATR IDs 32407, 31881, 31977

Cofense TriageTM: PM_Intel_Raccoon_31881, PM_Intel_Raccoon_31977

100% of malware-bearing phishing threats analyzed by the Cofense Phishing Defense CenterTM were reported by end users. 0% were stopped by technology. Condition users to be resilient to evolving phishing attacks with Cofense PhishMeTM and remove the blind spot with Cofense ReporterTM.

Quickly turn user reported emails into actionable intelligence with Cofense TriageTM. Reduce exposure time by rapidly quarantining threats with Cofense VisionTM.

Easily consume phishing-specific threat intelligence to proactively defend your organization against evolving threats with Cofense Intelligence TM.

Thanks to our unique perspective, no one knows more about REAL phishing threats than Cofense. To understand them better, read the 2019 Phishing Threat & Malware Review.

 

All third-party trademarks referenced by Cofense whether in logo form, name form or product form, or otherwise, remain the property of their respective holders, and use of these trademarks in no way indicates any relationship between Cofense and the holders of the trademarks. Any observations contained in this blog regarding circumvention of end point protections are based on observations at a point in time based on a specific set of system configurations. Subsequent updates or different configurations may be effective at stopping these or similar threats.