Symptoms of having OSAMiner installed on macOS are system freezes, problems with opening Activity Monitor (Activity Monitor.app), and higher CPU usage. The script is designed to kill running processes belonging to certain popular system monitoring and cleaning tools. The OSAMiner setup script uses a tool that prevents the infected computer from entering sleep mode. Research shows that OSAMiner embeds one run-only AppleScript inside another and uses the addresses on public websites to download an open-source Monero miner called XMR-STAK-RX – Free Monero RandomX Miner. OSAMiner was first detected in 2015 and is still successfully used by cyber criminals due to its complex structure (use of run-only AppleScript files), which prevents researchers from fully studying it and preventing the attacks. The post Malware Analysis Spotlight: OSAMiner Uses Run-Only AppleScripts to Evade Detection appeared first on VMRay.OSAMiner is a cryptocurrency miner, a Monero mining Trojan that uses run-only AppleScripts targeting Mac computers. Hxxp://ondayoncom:8080/ondayon.png (possibly backup URL)ĪV Detection Script embedded in First Stage 360 And for deeper analysis, the second and third stages are visible and available from the VMRay Analyzer Report. Within 2 minutes of analysis time, analysts can see a majority of the sample’s behavior, compared to hours of manual reverse engineering. Running the sample in VMRay gives analysts an immediate view into the key behaviors, characteristics, and IOCs. This file type won’t have a problem running on a victim’s machine but it is difficult for security teams to analyze because of the inherent obfuscation and limited tooling available. In addition, the second stage uses the system tool “caffeinate” to prevent the machine from going to sleep while the first stage will continuously query the running processes for common AV programs using the ps command: sh -c ps ax | grep -E '360|Keeper|MacMgr|Lemon|Malware|Avast|Avira|CleanMyMac' | grep -v grep | awk ''Īll of these actions are performed using sub-processes so they can be observed in the process graph and process overview.Īs we can see, this sample uses a different kind of evasion, using a rather uncommon file type, a compiled AppleScript, disguised as a PLIST file. The third stage is a zip file containing two dynamic libraries (dylibs) and finally a Mach-O binary, again disguised as a PLIST which can be clearly seen in the Files Tab. Write the mining configuration (pools.txt, config.txt, cpu.txt).Download and extract the third stage mining payload.The second stage is again executed using “osascript” and has two main tasks: All downloads are performed using curl which is clearly visible in the Behavior Tab. The second stage is another compiled AppleScript stored at ~/Library/11.png. The second one might be a fallback or used by another variant of the family. Interestingly, there are two URLs that were returned. The first request to budaybu100001com:8080 returns the second-stage URL embedded in the string “-=-=-=” as a marker. The Network Tab shows multiple C2 connections. Now we can dig deeper into each of these characteristics. From the Overview Tab, we can see the main behaviors of the sample including network connectivity, file dropping behavior, and system information gathering. Straight away, we see that a number of VMRay Threat Identifier (VTI) rules hit and the sample is classified as malicious. The “com.apple.4V.plist” file is placed in ~/Library/LaunchAgents by the original dropper and disguised as a Property list configuration file (PLIST) while it is in fact a compiled AppleScript. Note, at the time of analysis this sample of OSAMiner had a 2/60 detection rate on VirusTotal. In this Malware Analysis Spotlight, we will showcase the key behaviors identified during the dynamic analysis. We analyzed one of the latest samples “ com.apple.4V.plist” using VMRay Analyzer. In 2020, the SentinelLabs Team discovered that the malware authors were evolving their evasion techniques, adding more complexity by embedding one run-only AppleScript inside another. The authors of macOS.OSAMiner used run-only AppleScripts which made attempts at further analysis more difficult. This week the team at SentinelLabs released an in-depth analysis of macOS.OSAMiner, a Monero mining trojan infecting macOS users since 2015.
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