Likely eCrime Actor Capitalizing on Falcon Sensor Issues

Summary

On July 19, 2024, an issue present in a single content update for the CrowdStrike Falcon® sensor impacting Windows operating systems was identified, and a fix was deployed.¹

CrowdStrike Intelligence has since observed threat actors leveraging the event to distribute a malicious ZIP archive named crowdstrike-hotfix.zip. The ZIP archive contains a HijackLoader payload that, when executed, loads RemCos. Notably, Spanish filenames and instructions within the ZIP archive indicate this campaign is likely targeting Latin America-based (LATAM) CrowdStrike customers.

Details

On July 19, 2024, a ZIP archive named crowdstrike-hotfix.zip (SHA256 hash: c44506fe6e1ede5a104008755abf5b6ace51f1a84ad656a2dccc7f2c39c0eca2) was uploaded to an online malware-scanning service by a Mexico-based submitter. 

The ZIP file’s accompanying Spanish-language instructions appear to pose as a utility for automating recovery for the content update issue. The instructions prompt the user to run Setup.exe (SHA256 hash: 5ae3838d77c2102766538f783d0a4b4205e7d2cdba4e0ad2ab332dc8ab32fea9) to start the patch installation.

 

When executed, Setup.exe will load and execute the HijackLoader first-stage inside madBasic_.bpl (SHA256 hash: d6d5ff8e9dc6d2b195a6715280c2f1ba471048a7ce68d256040672b801fda0ea) via DLL search-order hijacking. 

HijackLoader — advertised as a private crypting service, ASMCrypt — is a modular multi-stage loader highly focused on evading detection. The HijackLoader configuration file named maidenhair.cfg (SHA256 hash: 931308cfe733376e19d6cd2401e27f8b2945cec0b9c696aebe7029ea76d45bf6) contains data that the loader leverages to execute the final RemCos payload, which contacts the command-and-control (C2) server at 213.5.130[.]58[:]433.

Following the content update issue, several typosquatting domains impersonating CrowdStrike have been identified. This campaign marks the first observed instance in which a threat actor has capitalized on the Falcon content issue to distribute malicious files targeting LATAM-based CrowdStrike customers.  

Recommendations

CrowdStrike Intelligence recommends that organizations ensure they are communicating with CrowdStrike representatives through official channels and adhere to technical guidance the CrowdStrike support teams have provided.

Falcon LogScale Queries

This Falcon LogScale query detects the activity described in this report:

// Hunting query for indicators (CSA-240835)

case { in("SHA256HashData", values=["931308cfe733376e19d6cd2401e27f8b2945cec0b9c696aebe7029ea76d45bf6", "c44506fe6e1ede5a104008755abf5b6ace51f1a84ad656a2dccc7f2c39c0eca2", "48a3398bbbf24ecd64c27cb2a31e69a6b60e9a69f33fe191bcf5fddbabd9e184", "d6d5ff8e9dc6d2b195a6715280c2f1ba471048a7ce68d256040672b801fda0ea"]); in("RemoteAddressIP4", values=["213.5.130.58"]) } | table([cid, aid, #event_simpleName, ComputerName])

Indicators of Compromise (IOCs)

Nombre del Archivo	SHA256 Hash
Crowdstrike-hotfix.zip	c44506fe6e1ede5a104008755abf5b6ace51f1a84ad656a2dccc7f2c39c0eca2
sqlite3.dll	02f37a8e3d1790ac90c04bc50de73cd1a93e27caf833a1e1211b9cc6294ecee5
vclx120.bpl	2bdf023c439010ce0a786ec75d943a80a8f01363712bbf69afc29d3e2b5306ed
instrucciones.txt	4f450abaa4daf72d974a830b16f91deed77ba62412804dca41a6d42a7d8b6fd0
maddisAsm_.bpl	52019f47f96ca868fa4e747c3b99cba1b7aa57317bf8ebf9fcbf09aa576fe006
Setup.exe	5ae3838d77c2102766538f783d0a4b4205e7d2cdba4e0ad2ab332dc8ab32fea9
datastate.dll	6010e2147a0f51a7bfa2f942a5a9eaad9a294f463f717963b486ed3f53d305c2
madexcept_.bpl	835f1141ece59c36b18e76927572d229136aeb12eff44cb4ba98d7808257c299
maidenhair.cfg (HijackLoader configuration)	931308cfe733376e19d6cd2401e27f8b2945cec0b9c696aebe7029ea76d45bf6
rtl120.bpl	b1fcb0339b9ef4860bb1ed1e5ba0e148321be64696af64f3b1643d1311028cb3
vcl120.bpl	b6f321a48812dc922b26953020c9a60949ec429a921033cfaf1e9f7d088ee628
battuta.flv	be074196291ccf74b3c4c8bd292f92da99ec37a25dc8af651bd0ba3f0d020349
madBasic_.bpl (HijackLoader first-stage)	d6d5ff8e9dc6d2b195a6715280c2f1ba471048a7ce68d256040672b801fda0ea
RemCos Payload	48a3398bbbf24ecd64c27cb2a31e69a6b60e9a69f33fe191bcf5fddbabd9e184
RemCos C2 Address	213.5.130[.]58[:]443

Table 1. Campaign IOCs

Additional Resources