Hearse

System installation

When the backdoor file is run, it drops the following two files to the Windows system directory:

• zopenssl.dll
• zopenssld.sys

Then the backdoor creates the following registry key: [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\zopenssl] "DllName" = "zopenssl.dll" Durin the system start, this registry key loads the backdoor main file, zopenssl.dll, to the address space of Winlogon.exe. When the DLL is activated, it starts the rootkit as a system service and runs the actual backdoor.The rootkit system service is activated using the following arguments:

• BinaryPathName: zopenssld.sys
• ServiceName: zopenssld
• DisplayName: OPENSSL cryptoapi

Hearse.A may also create the following files:

• nwr7.ies4
• bklks.ies4
• nwr8.ies4

Rootkit Hiding Techniques

Hearse.A is able to hide the following items:

• Files and directories

When it is active it hides its own files.Hearse.A installs and executes a kernel-mode driver (zopenssld.sys) to execute code in privilege level 0 (kernel mode). The kernel-mode code replaces the following function pointers from the system service table:

• NtCreateProcess
• NtCreateProcessEx
• NtQueryDirectoryFile

This allows it to inject code into any newly created process. In addition, it hides files or directories with any of the following names:

• nwr7.ies4
• zopenssl.dll
• bklks.ies4
• zopenssld.sys
• nwr8.ies4

Backdoor functionality

Hearse.A uses HTTP requests for communicating with a remote server controlled by the attacker. The server may request the infected system to perform any of the following actions:

• Run any program on the system
• Download additional files
• Spawn an interactive command shell
• Create and send a screenshot of the desktop
• Collect and send passwords and other account information
• Uninstall the backdoor

Hearse.A also starts up a SOCKS proxy on the infected system. The proxy port is reported back to the attacker by including it in the HTTP requests described above.