The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements
Present
AT
The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: A race condition must be won to successfully exploit the vulnerability. The successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker. The attack may need to be launched multiple times against a single target before being successful. Network injection. The attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
Scope
S
An exploited vulnerability can affect resources beyond the security scope managed by the security authority that is managing the vulnerable component. This is often referred to as a 'privilege escalation,' where the attacker can use the exploited vulnerability to gain control of resources that were not intended or authorized.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Ransom.AvosLocker / Code Execution
Discovery / credits: Malvuln - malvuln.com (c) 2022
Original source: https://malvuln.com/advisory/40f2238875fcbd2a92cfefc4846a15a8.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Ransom.AvosLocker
Vulnerability: Code Execution
Description: The ransomware looks for and executes DLLs in its current directory. Therefore, we can potentially hijack a vuln DLL execute our own code, control and terminate the malware pre-encryption. The exploit dll will check if the current directory is "C:\Windows\System32", if not we grab our process ID and terminate. We do not need to rely on hash signature or third-party product, the malware will do the work for us. Endpoint protection systems and or antivirus can potentially be killed prior to executing malware, but this method cannot as theres nothing to kill the DLL just lives on disk waiting. From defensive perspective you can add the DLLs to a specific network share containing important data as a layered approach. All basic tests were conducted successfully in a virtual machine environment.
Family: AvosLocker
Type: PE32
MD5: 40f2238875fcbd2a92cfefc4846a15a8
Vuln ID: MVID-2022-0573
Disclosure: 05/02/2022
Video PoC URL: https://www.youtube.com/watch?v=jCxG46dEmso
Exploit/PoC:
1) Compile the following C code as "mpr.dll"
2) Place the DLL in same directory as the ransomware
3) Optional - Hide it: attrib +s +h "mpr.dll"
4) Run the malware
#include "windows.h"
#include "stdio.h"
//By malvuln - 5/2/2022
//Vuln: Code Execution
//Target: Ransom.AvosLocker
//MD5: 40f2238875fcbd2a92cfefc4846a15a8
/** DISCLAIMER:
Author is NOT responsible for any damages whatsoever by using this software or improper malware
handling. By using this code you assume and accept all risk implied or otherwise.
**/
//gcc -c mpr.c -m32
//gcc -shared -o mpr.dll mpr.o -m32
BOOL APIENTRY DllMain(HINSTANCE hInst, DWORD reason, LPVOID reserved){
switch (reason) {
case DLL_PROCESS_ATTACH:
MessageBox(NULL, "Code Exec", "by malvuln", MB_OK);
TCHAR buf[MAX_PATH];
GetCurrentDirectory(MAX_PATH, TEXT(buf));
//printf("Current directory: %s\n", buf);
//check the path
int rc = strcmp("C:\\Windows\\System32", TEXT(buf));
if(rc != 0){
HANDLE handle = OpenProcess(PROCESS_TERMINATE, FALSE, getpid());
if (NULL != handle) {
TerminateProcess(handle, 0);
CloseHandle(handle);
}
}
break;
}
return TRUE;
}
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