Rewterz Threat Alert – Credential Stealer Targeting Banks in US, Canada and India

Severity

Medium

Analysis Summary

Threat actors have been discovered distributing a new credential stealer written in AutoHotkey (AHK) scripting language as part of an ongoing campaign that started early 2020. Customers of financial institutions in the US and Canada are among the primary targets for credential exfiltration, with a specific focus on banks such as Scotiabank, Royal Bank of Canada, HSBC, Alterna Bank, Capital One, Manulife, and EQ Bank, as well as an Indian banking firm ICICI Bank. The multi-stage infection chain commences with a malware-laced Excel file that’s embedded with a Visual Basic for Applications (VBA) AutoOpen macro, which is subsequently used to drop and execute the downloader client script (“adb.ahk”) via a legitimate portable AHK script compiler executable (“adb.exe”). 

The downloader client script is also responsible for achieving persistence, profiling victims, and downloading and running additional AHK scripts from command-and-control (C&C) servers located in the US, the Netherlands, and Sweden. What makes this malware different is that instead of receiving commands directly from the C&C server, it downloads and executes AHK scripts to accomplish different tasks. Chief among them is a credential stealer that targets various browsers such as Google Chrome, Opera, Microsoft Edge, and more. Once installed, the stealer also attempts to download an SQLite module (“sqlite3.dll”) on the infected machine, using it to perform SQL queries against the SQLite databases within browsers’ app folders. In the final step, the stealer collects and decrypts credentials from browsers and exfiltrates the information to the C&C server in plaintext via an HTTP POST request.

Impact

• Credential Theft
• Data Exfiltration
• Unauthorized Access

Indicators of Compromise

MD5

• 41190583bbbb2fd7f355c2e42b2d70a3
• 33e9cc02c07a2bf4af4123779f405126

SHA-256

• bed925d7c0af493c9ccd2828d6fdefe6f4255bada51f645a8fffdd67e24b87fd
• 27d9eb869eea6c713c6f109eca867844e2feceb0783bda2b78f7a92dffc833f6

SHA1

• 9c9ebef0dc57e363dd3ce03bf2f29d2e6146a2d5
• ebb94b5b3cd8378d15a3c14c8d401d927cc81464

Source IP

• 93[.]115[.]23[.]48
• 94[.]103[.]94[.]186
• 2[.]56[.]215[.]97
• 199[.]192[.]29[.]202
• 5[.]39[.]223[.]162

Remediation

• Block the threat indicators at their respective controls.
• Do not download files attached in untrusted emails.