DeliveryCheck
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Groups observed using it
2 distinct threat actors attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
When activated, these macros execute a PowerShell command, creating a scheduled task impersonating a Firefox browser updater. However, this task downloads the DeliveryCheck backdoor (also known as CapiBar and GAMEDAY) and launches it in memory, where it connects to the threat actor's command and control server to receive commands to execute or deploy further malware payloads.
When activated, these macros execute a PowerShell command, creating a scheduled task impersonating a Firefox browser updater. However, this task downloads the DeliveryCheck backdoor (also known as CapiBar and GAMEDAY) and launches it in memory, where it connects to the threat actor's command and control server to receive commands to execute or deploy further malware payloads.
Techniques & procedures
14 distinct techniques documented for this family, organized by ATT&CK tactic.
Initial Access
1 techniqueThe attacks start with phishing emails containing Excel XLSM attachments that contain malicious macros.
Execution
4 techniquesWhen activated, these macros execute a PowerShell command, creating a scheduled task impersonating a Firefox browser updater.
Microsoft says that these malware payloads are embedded and launched from XSLT stylesheets.
When activated, these macros execute a PowerShell command, creating a scheduled task impersonating a Firefox browser updater.
The attacks start with phishing emails containing Excel XLSM attachments that contain malicious macros. When activated, these macros execute a PowerShell command...
Persistence
3 techniquesWhen activated, these macros execute a PowerShell command, creating a scheduled task impersonating a Firefox browser updater.
What makes DeliveryCheck stand out is a Microsoft Exchange server-side component that turns the server into a command and control server for the threat actors.
Privilege Escalation
2 techniquesStealth
3 techniques...creating a scheduled task impersonating a Firefox browser updater.
Microsoft says that these malware payloads are embedded and launched from XSLT stylesheets.
"Окрім застосування XSLT (Extensible Stylesheet Language Transformations)..."
Command and Control
3 techniques...launches it in memory, where it connects to the threat actor's command and control server to receive commands to execute or deploy further malware payloads.
Multiple C2 URLs over HTTPS, including Exchange-themed paths like "/outlook/api/logon.aspx" and "/.../RPCWITHCERT/SYNC".
...connects to the threat actor's command and control server to receive commands to execute or deploy further malware payloads.
Exfiltration
1 techniqueAfter infecting devices, the threat actors utilize the backdoor to exfiltrate data from the compromised devices using the Rclone tool.
Recent activity
3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Malware/tool used alongside Kazuar in targeted Turla attacks; CAPIBAR is named in the title while DeliveryCheck is listed with the report.
A backdoor used by Turla/Secret Blizzard in phishing-led attacks against the defense sector and Microsoft Exchange environments. It is launched in memory, connects to C2 for tasking and payload delivery, and includes a server-side Microsoft Exchange component that can turn a legitimate Exchange server into a malware-distribution and command-and-control server.
DeliveryCheck [[URL_b3187638_112]] 2023 年 11 月 (v 5.119)
The version that knows your environment.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.