Function at 0x439260
Capabilities:
Access the windows event log
Create a process with modified i/o handles and window
Create process on windows
Get session user name
Query or enumerate registry value

Disassembly:
push ebp
mov ebp, esp
push ebx
push edi
push esi
sub esp, 0xa8
mov edi, ecx
mov eax, dword [0x4a0070]
xor eax, ebp
mov dword [ebp - 0x10], eax
lea esi, [ebp - 0xa8]
mov ecx, esi
xor edx, edx
push str.SetDefaultBrowserUserChoice
call fcn.0042e270
add esp, 4
cmp dword [esi + 4], 0
jne 0x4393f9
movzx eax, word [ebp - 0xa8]
cmp eax, 0x100
jb 0x4393f9
movzx eax, al
test ax, ax
je 0x4393f9
mov ecx, edi
xor edx, edx
call fcn.00431a40
test eax, eax
js 0x4393f9
lea edi, [ebp - 0x2c]
mov ecx, edi
mov edx, str.firefox.exe
call fcn.00436d50
cmp dword [edi + 0x18], 0
jne 0x4393e4
movsd xmm0, qword [ebp - 0x1c]
lea ebx, [ebp - 0x44]
movsd qword [ebx + 0x10], xmm0
movups xmm0, xmmword [ebp - 0x2c]
movups xmmword [ebx], xmm0
cmp dword [ebx + 0x14], 8
mov eax, ebx
jb 0x439300
mov eax, dword [ebp - 0x44]
lea edi, [ebp - 0x4c]
mov dword [edi], eax
mov dword [edi + 4], str._to_handle_default_browser_agent
lea ecx, [ebp - 0x54]
mov edx, 2
push edi
call fcn.00405620
add esp, 4
xorps xmm0, xmm0
movups xmmword [ebp - 0x74], xmm0
movups xmmword [ebp - 0x84], xmm0
movups xmmword [ebp - 0x94], xmm0
movups xmmword [ebp - 0xa4], xmm0
mov dword [ebp - 0xa8], 0x44
lea eax, [ebp - 0x54]
mov edi, dword [eax]
cmp dword [ebp - 0x30], 8
jb 0x439351
mov ebx, dword [ebp - 0x44]
sub esp, 0x28
lea eax, [ebp - 0x64]
mov dword [esp + 0x24], eax
mov dword [esp + 0x20], esi
xor esi, esi
mov dword [esp + 0x1c], esi
mov dword [esp + 0x18], esi
movaps xmm0, xmmword [0x4630e0]
movups xmmword [esp + 8], xmm0
mov dword [esp + 4], edi
mov dword [esp], ebx
call dword [sym.imp.KERNEL32.dll_CreateProcessW]
test eax, eax
je 0x439436
mov esi, dword [sym.imp.KERNEL32.dll_CloseHandle]
push dword [ebp - 0x60]
call esi
push dword [ebp - 0x64]
call esi
test edi, edi
je 0x4393a7
push edi
call fcn.0044fa60
add esp, 4
mov eax, dword [ebp - 0x30]
cmp eax, 8
jb 0x4393e4
mov ecx, dword [ebp - 0x44]
lea esi, [eax + eax]
add esi, 2
cmp esi, 0x1000
jb 0x4393da
mov edx, dword [ecx - 4]
add ecx, 0xfffffffc
sub ecx, edx
cmp ecx, 0x20
jae 0x439515
add eax, eax
add eax, 0x25
mov esi, eax
mov ecx, edx
push esi
push ecx
call fcn.0044fa95
add esp, 8
mov ecx, dword [ebp - 0x10]
xor ecx, ebp
call fcn.00450110
add esp, 0xa8
pop esi
pop edi
pop ebx
pop ebp
ret
call dword [sym.imp.KERNEL32.dll_GetLastError]
push eax
push 0x119
push str.SetDefaultBrowserFromNotification
push str.Failed_to_SetDefaultBrowserUserChoice:__X
push dword [sym.default_browser_agent.exe_gWinEventLogSourceName]
call fcn.0042a580
add esp, 0x14
mov ecx, dword [ebp - 0x10]
xor ecx, ebp
call fcn.00450110
add esp, 0xa8
pop esi
pop edi
pop ebx
pop ebp
jmp fcn.004527a0
call dword [sym.imp.KERNEL32.dll_GetLastError]
movzx ecx, ax
or ecx, 0x80070000
test eax, eax
cmovle ecx, eax
mov dword [ebp - 0xac], ecx
mov eax, dword [sym.default_browser_agent.exe_gWinEventLogSourceName]
mov dword [ebp - 0xb4], eax
mov edx, 0xf4
mov ebx, str.LaunchFirefoxToHandleDefaultBrowserAgent
mov eax, str.0x_X_in__S:_d
push edx
push ebx
push ecx
push eax
call fcn.00452550
add esp, 0x10
lea ecx, [eax + 1]
mov dword [ebp - 0xb0], ecx
lea ecx, [eax + eax]
add ecx, 2
xor ebx, ebx
dec ebx
cmp eax, 0xffffffff
cmovge ebx, ecx
push ebx
call fcn.0044fa57
add esp, 4
push ebx
push esi
mov ebx, eax
push eax
call sub.VCRUNTIME140.dll_memset
add esp, 0xc
mov eax, 0xf4
push eax
mov eax, str.LaunchFirefoxToHandleDefaultBrowserAgent
push eax
push dword [ebp - 0xac]
mov eax, str.0x_X_in__S:_d
push eax
push 0xffffffffffffffff
push dword [ebp - 0xb0]
push ebx
call fcn.004525b0
add esp, 0x1c
push dword [ebp - 0xb4]
push esi
mov esi, ebx
call dword [sym.imp.ADVAPI32.dll_RegisterEventSourceW]
test eax, eax
je 0x439507
mov ebx, eax
lea eax, [ebp - 0x50]
mov dword [eax], esi
xor ecx, ecx
xor edx, edx
inc edx
push ecx
push eax
push ecx
push edx
push ecx
push dword [ebp - 0xac]
push ecx
push edx
push ebx
call dword [sym.imp.ADVAPI32.dll_ReportEventW]
push ebx
call dword [sym.imp.ADVAPI32.dll_DeregisterEventSource]
push esi
call fcn.0044fa60
add esp, 4
jmp 0x43939a
call dword [sym.imp.api_ms_win_crt_runtime_l1_1_0.dll__invalid_parameter_noinfo_noreturn]
int3