YARA · Malpedia signator rules
MALPEDIA_Win_Krdownloader_Auto
autogenerated rule brought to you by yara-signator
MalwareKrdownloaderMalpedia signator rulesCreative Commons Attribution-ShareAlike 4.0Compiles with YARA-X
- Author
- Felix Bilstein - yara-signator at cocacoding dot com
- Date
- 2026-05-04
- Modified
- 2026-05-18
- Score / Quality
- 75 / 75
What this rule detects
autogenerated rule brought to you by yara-signator
Associated malware family: Krdownloader.
It defines 10 patterns (0 text, 10 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
win-krdownloader-auto.yarCreative Commons Attribution-ShareAlike 4.0
rule MALPEDIA_Win_Krdownloader_Auto : FILE
{
meta:
= "autogenerated rule brought to you by yara-signator"
= "Felix Bilstein - yara-signator at cocacoding dot com"
= "9b4c2382-c7c9-51bb-a270-db7f3b8fdc18"
= "2026-05-04"
= "2026-05-18"
= "https://malpedia.caad.fkie.fraunhofer.de/details/win.krdownloader"
= "https://github.com/malpedia/signator-rules//blob/c901f97b7df03e41917da74c2a84b04c227316c2/rules/win.krdownloader_auto.yar#L1-L123"
= "N/A"
= "e426897d5051d34441bbf890d389e196e8737ba70d93e788b3dc9bdf9efdea1d"
= 75
= 75
= "FILE"
= "1"
= "yara-signator v0.6.0"
= "callsandjumps;datarefs;binvalue"
= "20260422"
= "a182e35da64e6d71cb55f125c4d4225196523f14"
= "20260504"
= "CC BY-SA 4.0"
= "TLP:WHITE"
strings:
$sequence_0 = { 8b0a 2b08 8bc1 99 b904050000 f7f9 }
$sequence_1 = { 8d95e9fbffff 52 e8???????? 83c40c 8b45fc 2b45f4 50 }
$sequence_2 = { 6840004004 8d45f4 50 68???????? 68???????? }
$sequence_3 = { e8???????? 8945ac 8b4dd8 0fbe540de8 52 8b45d4 0fbe4c05e8 }
$sequence_4 = { 83c408 837d1000 7509 c745f801000000 eb07 }
$sequence_5 = { 6a00 6840004004 8d45f4 50 68???????? 68???????? }
$sequence_6 = { 837dec00 0f850a010000 8b4df8 894dfc 837dfc00 0f84fa000000 }
$sequence_7 = { 894df8 c745fc00000000 c745f400000000 eb0c 8b45f8 8b4df4 034804 }
$sequence_8 = { 50 680000a000 8b4dec 51 6a00 }
$sequence_9 = { c745bc00000000 c745e002000000 c745e8983a0000 8b45e8 50 }
condition:
7 of them and filesize < 352256
}
Strings (10 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $sequence_0 | hex | { 8b0a 2b08 8bc1 99 b904050000 f7f9 } | |
| $sequence_1 | hex | { 8d95e9fbffff 52 e8???????? 83c40c 8b45fc 2b45f4 50 } | |
| $sequence_2 | hex | { 6840004004 8d45f4 50 68???????? 68???????? } | |
| $sequence_3 | hex | { e8???????? 8945ac 8b4dd8 0fbe540de8 52 8b45d4 0fbe4c05e8 } | |
| $sequence_4 | hex | { 83c408 837d1000 7509 c745f801000000 eb07 } | |
| $sequence_5 | hex | { 6a00 6840004004 8d45f4 50 68???????? 68???????? } | |
| $sequence_6 | hex | { 837dec00 0f850a010000 8b4df8 894dfc 837dfc00 0f84fa000000 } | |
| $sequence_7 | hex | { 894df8 c745fc00000000 c745f400000000 eb0c 8b45f8 8b4df4 034804 } | |
| $sequence_8 | hex | { 50 680000a000 8b4dec 51 6a00 } | |
| $sequence_9 | hex | { c745bc00000000 c745e002000000 c745e8983a0000 8b45e8 50 } |
Condition
7 of them and filesize < 352256In plain words (Heuristic)
- The file must be smaller than 352256 (a cheap guard that skips large files).
- At least 7 patterns in the rule must match.
Test this rule in your browser
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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.
Licence & attribution
Author: Felix Bilstein - yara-signator at cocacoding dot com
Source repository: Malpedia signator rules @ c901f97b7d
Licence: Creative Commons Attribution-ShareAlike 4.0 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 9b4c2382-c7c9-51bb-a270-db7f3b8fdc18
Metadata
| version | 1 |
|---|---|
| tool | yara-signator v0.6.0 |
| signator_config | callsandjumps;datarefs;binvalue |
| malpedia_rule_date | 20260422 |
| malpedia_hash | a182e35da64e6d71cb55f125c4d4225196523f14 |
| malpedia_version | 20260504 |
| malpedia_license | CC BY-SA 4.0 |
| malpedia_sharing | TLP:WHITE |
Tags:FILE
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