YARA · Embee Research
EMBEERESEARCH_Win_Njrat_Strings_Oct_2023
- Author
- Matthew @ Embee_Research
- Date
- 2023-10-03
- Score / Quality
- 75 / 75
What this rule detects
Associated malware family: Njrat.
Targets: .NET assembly.
It defines 6 patterns (6 text, 0 hex, 0 regex). YARA modules used: dotnet.
Summary generated from the rule's metadata and condition.
Rule source
Includes the imports needed to compile it on its own.
import "dotnet"
rule EMBEERESEARCH_Win_Njrat_Strings_Oct_2023
{
meta:
= ""
= "Matthew @ Embee_Research"
= "c89711cb-aae9-5409-80c2-145a8d5fca56"
= "2023-10-03"
= "2023-10-03"
= "https://github.com/embee-research/Yara-detection-rules/"
= "https://github.com/embee-research/Yara-detection-rules//blob/ac56d6f6fd2a30c8cb6e5c0455d6519210a8b0f4/Rules/win_njrat_strings_oct_2023.yar#L3-L25"
= "N/A"
= "59d6e2958780d15131c102a93fefce6e388e81da7dc78d9c230aeb6cab7e3474"
= "ed36a991aa2699486f1ef34f4f4d559a3dd351180602f017ad7d868e146c703b"
= 75
= 75
= ""
strings:
$s1 = "netsh firewall delete allowedprogram" wide
$s2 = "cmd.exe /c ping 0 -n 2 & del" wide
$s3 = "netsh firewall add allowedprogram" wide
$s4 = "Execute ERROR" wide
$s5 = "Update ERROR" wide
$s6 = "Download ERROR" wide
condition:
dotnet.is_dotnet and ( all of ( $s* ) )
}
Strings (6 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $s1 | text | "netsh firewall delete allowedprogram" | wide |
| $s2 | text | "cmd.exe /c ping 0 -n 2 & del" | wide |
| $s3 | text | "netsh firewall add allowedprogram" | wide |
| $s4 | text | "Execute ERROR" | wide |
| $s5 | text | "Update ERROR" | wide |
| $s6 | text | "Download ERROR" | wide |
Condition
dotnet.is_dotnet and ( all of ( $s* ) )In plain words (Heuristic)
- All patterns in ( $s* ) must match.
- Uses the dotnet module.
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- 59d6e2958780d15131c102a93fefce6e388e81da7dc78d9c230aeb6cab7e3474
Licence & attribution
Author: Matthew @ Embee_Research
Source repository: Embee Research @ ac56d6f6fd
Licence: Detection Rule License 1.1 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: c89711cb-aae9-5409-80c2-145a8d5fca56
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