ZIP files are used by threat actors to weaponize them since they can easily convey malicious payloads within compressed archives, making it difficult for security systems to detect and study the file’s contents.
These files can be used to deliver multiple files to the target users so that attackers can take advantage of vulnerabilities or perform a number of other malicious operations as soon as these files are extracted.
Recently the cybersecurity analysts at ANY.RUN discovered that hackers are actively using the weaponized ZIP file to steal NTLM hashes.
Technical Analysis
Cybersecurity researchers warned of a new threat, between February 23, 2024, and the present moment they observed a mass attack on users.
Here the complete scenario begins with the receipt of an email having a ZIP attachment and an inquiry in both English and German that says, “I sent a material your side last day have you able to get it?” Among these compressed files are two different documents one of which turns out to be a weaponized HTML page.
The trick here is that this HTML page is very much intricately crafted upon a 450-byte template. More specifically, the redirection works by transferring encrypted HTTP traffic through several nodes.
This is done with the help of Google App Script (GAS) as it receives requests from compromised systems, and this item employs the SMB protocol for its implementation.
However, these attackers have implemented impacket-smbserver tool on their servers. It adds complexity and sophistication that points to a well-planned strategy in their cyber activities.
Attack chain (Source – Any.Run)
The following user data is obtained by the attackers when the HTML content is opened:-
- IP address
- NTLM challenge data
- Username
- Victim’s computer name
MITRE
- Phishing (T1566)
- User and PC name enumeration (T1589)
- NTLM compromise (T1187)
Queries
Here below we have mentioned all the queries that are recommended by the experts:-
- SuricataID:”8001377″
- SuricataID:”8001065″
- SuricataID:”8000547″
Besides this researchers will keep an eye on the progression of this attack in the hopes that it may enable users to examine their email attachments on the platform.
