UPPERCUT
UPPERCUT is a 32-bit HTTP-based backdoor that has been used by menuPass since at least 2017.[1] Once thought to be exclusive to menuPass, UPPERCUT was also observed being used by menuPass-associated MirrorFace during Operation AkaiRyū.[2]
Associated Software Descriptions
| Name | Description |
|---|---|
| ANEL |
Techniques Used
| Domain | ID | Name | Use | |
|---|---|---|---|---|
| Enterprise | T1548 | .002 | Abuse Elevation Control Mechanism: Bypass User Account Control | |
| Enterprise | T1071 | .001 | Application Layer Protocol: Web Protocols |
UPPERCUT has used HTTP for C2, including sending error codes in cookie headers.[1][2][4] |
| Enterprise | T1059 | .003 | Command and Scripting Interpreter: Windows Command Shell |
UPPERCUT uses cmd.exe to execute commands on the victim’s machine.[1] |
| Enterprise | T1132 | .001 | Data Encoding: Standard Encoding | |
| Enterprise | T1005 | Data from Local System |
UPPERCUT can upload files to the C2 from infected machines.[3][2] |
|
| Enterprise | T1678 | Delay Execution | ||
| Enterprise | T1573 | .001 | Encrypted Channel: Symmetric Cryptography |
Some versions of UPPERCUT have used the hard-coded string "this is the encrypt key" for Blowfish encryption when communicating with a C2. Later versions have hard-coded keys uniquely for each C2 address.[1] UPPERCUT has also used custom ChaCha20, XOR, and LZO algorithms for C2 communication.[3][2] |
| Enterprise | T1083 | File and Directory Discovery |
UPPERCUT has the capability to gather the victim's current directory.[1] |
|
| Enterprise | T1574 | .001 | Hijack Execution Flow: DLL |
UPPERCUT has been sideloaded through a legitimately signed application from the JustSystems Corporation.[4] |
| Enterprise | T1105 | Ingress Tool Transfer |
UPPERCUT can download and upload files to and from the victim’s machine.[1][3][2] |
|
| Enterprise | T1113 | Screen Capture |
UPPERCUT can capture desktop screenshots in the PNG format and send them to the C2 server.[1][3][2][4] |
|
| Enterprise | T1082 | System Information Discovery |
UPPERCUT has the capability to gather the system’s hostname and OS version.[1][2] |
|
| Enterprise | T1016 | System Network Configuration Discovery |
UPPERCUT has the capability to gather the victim's proxy information.[1] |
|
| Enterprise | T1033 | System Owner/User Discovery |
UPPERCUT has the capability to collect the current logged on user’s username from a machine.[1] |
|
| Enterprise | T1124 | System Time Discovery |
UPPERCUT has the capability to obtain the time zone information and the current timestamp of the victim’s machine.[1] |
|
Groups That Use This Software
| ID | Name | References |
|---|---|---|
| G0045 | menuPass | |
| G1054 | MirrorFace |
Campaigns
| ID | Name | Description |
|---|---|---|
| C0060 | Operation AkaiRyū |
During Operation AkaiRyū, MirrorFace used UPPERCUT.[2][4] |