Misdat_Backdoor
YARA-2025-1119
High
general
Active
No description available for this rule
Misdat_Backdoor.yar
Valid Syntax
rule Misdat_Backdoor
{
meta:
author = "Cylance SPEAR Team"
/* Decode Function
CODE:00406C71 8B 55 F4 mov edx, [ebp+var_C]
CODE:00406C74 8A 54 1A FF mov dl, [edx+ebx-1]
CODE:00406C78 8B 4D F8 mov ecx, [ebp+var_8]
CODE:00406C7B C1 E9 08 shr ecx, 8
CODE:00406C7E 32 D1 xor dl, cl
CODE:00406C80 88 54 18 FF mov [eax+ebx-1], dl
CODE:00406C84 8B 45 F4 mov eax, [ebp+var_C]
CODE:00406C87 0F B6 44 18 FF movzx eax, byte ptr [eax+ebx-1]
CODE:00406C8C 03 45 F8 add eax, [ebp+var_8]
CODE:00406C8F 69 C0 D9 DB 00 00 imul eax, 0DBD9h
CODE:00406C95 05 3B DA 00 00 add eax, 0DA3Bh
CODE:00406C9A 89 45 F8 mov [ebp+var_8], eax
CODE:00406C9D 43 inc ebx
CODE:00406C9E 4E dec esi
CODE:00406C9F 75 C9 jnz short loc_406C6A
*/
strings:
$imul = {03 45 F8 69 C0 D9 DB 00 00 05 3B DA 00 00}
$delphi = {50 45 00 00 4C 01 08 00 19 5E 42 2A}
condition:
$imul and $delphi
}Rule Metadata
author
Cylance SPEAR Team
String Definitions
{"name":"$imul","value":"{03 45 F8 69 C0 D9 DB 00 00 05 3B DA 00 00}"}
{"name":"$delphi","value":"{50 45 00 00 4C 01 08 00 19 5E 42 2A}"}
Threat Analysis
This YARA rule is designed to detect general threats.
Severity Level: High
The rule uses pattern matching to identify specific byte sequences, strings, or behavioral patterns associated with malicious activity.
Detection Capabilities
- File-based detection for executables and documents
- Memory scanning for running processes
- Network traffic analysis support
Command Line Usage
# Scan a single file yara Misdat_Backdoor.yar /path/to/suspicious/file # Scan a directory recursively yara -r Misdat_Backdoor.yar /path/to/directory/ # Scan with metadata output yara -m Misdat_Backdoor.yar target_file # Scan process memory (Linux) yara Misdat_Backdoor.yar /proc/[pid]/exe
Integration Examples
Python (yara-python)
import yara
rules = yara.compile(filepath='Misdat_Backdoor.yar')
matches = rules.match('/path/to/file')
ClamAV Integration
clamscan --yara-rules=Misdat_Backdoor.yar /path/to/scan
Rule Information
YARA ID
YARA-2025-1119
Author
Repository
Created
August 19, 2025
Last Updated
August 19, 2025
Last Imported
Never
Threat Intelligence
Risk Level
High
Category
general
Detection Confidence
Analysis Pending
False Positive Rate
Not Available
Last Seen in Wild
No Data
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