CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
AI Score
Confidence
High
EPSS
Percentile
39.7%
/*
Title: Armadito Antivirus - Malware Detection Bypass
Date: 21/02/2018
Author: Souhail Hammou
Author's website: http://rce4fun.blogspot.com
Vendor Homepage: http://www.teclib-edition.com/en/
Version: 0.12.7.2
CVE: CVE-2018-7289
Details:
--------
An issue was discovered in armadito-windows-driver/src/communication.c affecting Armadito 0.12.7.2 and previous versions.
Malware with filenames containing pure UTF-16 characters can bypass detection.
The user-mode service will fail to open the file for scanning after the conversion is done from Unicode to ANSI.
This happens because characters that cannot be converted from Unicode are replaced with the '?' character.
The code responsible for this issue is located in armadito-windows-driver/src/communication.c
========================================================================================================
// Convert unicode string to ansi string for ring 3 process.
ntStatus = RtlUnicodeStringToAnsiString(&AnsiString, (PCUNICODE_STRING)FilePath, TRUE);
if(!NT_SUCCESS(ntStatus)){
DbgPrint("[-] Error :: ArmaditoGuard!SendScanOrder :: RtlUnicodeStringToAnsiString() routine failed !! \n");
__leave;
}
========================================================================================================
The two examples below demonstrate the bug.
In the first case, the filename is in Arabic and in the second, the filename's first letter is the greek M (U+039C).
Original filename:
Ω
Ψ±ΨΨ¨Ψ§.exe : 0645 0631 062d 0628 0627 002e 0065 0078 0065
Converted to ANSI by Armadito:
?????.exe : 3f 3f 3f 3f 3f 2e 65 78 65
=============================
Original filename:
Ξalware.exe : 039c 0061 006c 0077 0061 0072 0065 002e 0065 0078 0065
Converted to ANSI by Armadito:
?alware.exe : 3f 61 6c 77 61 72 65 2e 65 78 65
See: https://github.com/armadito/armadito-windows-driver/issues/5
*/
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
AI Score
Confidence
High
EPSS
Percentile
39.7%