Octowave Loader

Octowave Loader is a malware loader used to run other families of malware. This is often made up of an MSI or Inno Setup installer for a legitimate piece of software that has been trojanised to include a number of malicious DLLs which inevitably load and run malicious code often stored within a WAV file that is also delivered to an endpoint. In the wild this has been seen delivered through fake software installers and ClickFix / Fake Captcha campaigns. Families of malware deployed often include information stealers, NetSupport RAT, and potentially bots like Danabot.

author = "Felix Bilstein - yara-signator at cocacoding dot com"

info = "autogenerated rule brought to you by yara-signator"

signator_config = "callsandjumps;datarefs;binvalue"

malpedia_reference = "

malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"

* The strings used in this rule have been automatically selected from the

* disassembly of memory dumps and unpacked files, using YARA-Signator.

* The code and documentation is published here:

*

* As Malpedia is used as data source, please note that for a given

* number of families, only single samples are documented.

* This likely impacts the degree of generalization these rules will offer.

* Take the described generation method also into consideration when you

* apply the rules in your use cases and assign them confidence levels.

$sequence_0 = { ffd0 84c0 7527 807c241401 7513 384334 740e }

// ffd0 | call eax

// 84c0 | test al, al

// 7527 | jne 0x29

// 807c241401 | cmp byte ptr [esp + 0x14], 1

// 7513 | jne 0x15

// 384334 | cmp byte ptr [ebx + 0x34], al

// 740e | je 0x10

$sequence_1 = { ff7514 ff7510 ff750c ff7508 e8???????? 84c0 7518 }

// ff7514 | push dword ptr [ebp + 0x14]

// ff7510 | push dword ptr [ebp + 0x10]

// ff750c | push dword ptr [ebp + 0xc]

// ff7508 | push dword ptr [ebp + 8]

// 84c0 | test al, al

// 7518 | jne 0x1a

$sequence_2 = { ff75f8 ff75f4 57 e8???????? ff75e8 894610 e8???????? }

// ff75f8 | push dword ptr [ebp - 8]

// ff75f4 | push dword ptr [ebp - 0xc]

// 57 | push edi

// ff75e8 | push dword ptr [ebp - 0x18]

// 894610 | mov dword ptr [esi + 0x10], eax

$sequence_3 = { bd08000000 e8???????? 83c408 33f6 8b4308 0fb60430 50 }

// bd08000000 | mov ebp, 8

// 83c408 | add esp, 8

// 33f6 | xor esi, esi

// 8b4308 | mov eax, dword ptr [ebx + 8]

// 0fb60430 | movzx eax, byte ptr [eax + esi]

// 50 | push eax

$sequence_4 = { ff34857c712d10 8d46ff 50 ff7518 e8???????? 8b55f8 83c410 }

// ff34857c712d10 | push dword ptr [eax*4 + 0x102d717c]

// 8d46ff | lea eax, [esi - 1]

// 50 | push eax

// ff7518 | push dword ptr [ebp + 0x18]

// 8b55f8 | mov edx, dword ptr [ebp - 8]

// 83c410 | add esp, 0x10

$sequence_5 = { e8???????? 8bc8 83f9ff 0f8413010000 8bc6 83ff0f 7602 }

// 8bc8 | mov ecx, eax

// 83f9ff | cmp ecx, -1

// 0f8413010000 | je 0x119

// 8bc6 | mov eax, esi

// 83ff0f | cmp edi, 0xf

// 7602 | jbe 4

$sequence_6 = { f30f5c442454 0f28e3 f30f114c241c f30f59e1 f30f100d???????? f30f11442404 f30f59442470 }

// f30f5c442454 | subss xmm0, dword ptr [esp + 0x54]

// 0f28e3 | movaps xmm4, xmm3

// f30f114c241c | movss dword ptr [esp + 0x1c], xmm1

// f30f59e1 | mulss xmm4, xmm1

// f30f11442404 | movss dword ptr [esp + 4], xmm0

// f30f59442470 | mulss xmm0, dword ptr [esp + 0x70]

$sequence_7 = { ff86201b0000 8b86201b0000 c684302013000000 52 55 ff742420 ff74242c }

// ff86201b0000 | inc dword ptr [esi + 0x1b20]

// 8b86201b0000 | mov eax, dword ptr [esi + 0x1b20]

// c684302013000000 | mov byte ptr [eax + esi + 0x1320], 0

// 52 | push edx

// 55 | push ebp

// ff742420 | push dword ptr [esp + 0x20]

// ff74242c | push dword ptr [esp + 0x2c]

$sequence_8 = { f30f59f7 f30f5cd8 f30f58e6 0f28f3 39442470 7e5a 8b4c247c }

// f30f59f7 | mulss xmm6, xmm7

// f30f5cd8 | subss xmm3, xmm0

// f30f58e6 | addss xmm4, xmm6

// 0f28f3 | movaps xmm6, xmm3

// 39442470 | cmp dword ptr [esp + 0x70], eax

// 7e5a | jle 0x5c

// 8b4c247c | mov ecx, dword ptr [esp + 0x7c]

$sequence_9 = { ff742420 ff742420 68???????? 56 e8???????? 0fb6442476 50 }

// ff742420 | push dword ptr [esp + 0x20]

// ff742420 | push dword ptr [esp + 0x20]

// 56 | push esi

// 0fb6442476 | movzx eax, byte ptr [esp + 0x76]

// 50 | push eax

(20250411 | Detects resources embedded within Octowave Loader MSI installers)

author = "Jai Minton (@CyberRaiju) - HuntressLabs"

description = "Detects resources embedded within Octowave Loader MSI installers"

license = "Detection Rule License 1.1

yt_reference = "

reference = "

hash1 = "05b025b8475c0acbc9a5d2cd13c15088a2fb452aa514d0636f145e1c4c93e6ee"

hash2 = "500462c4fb6e4d0545f04d63ef981d9611b578948e5cfd61d840ff8e2f206587"

hash3 = "5ee9e74605b0c26b39b111a89139d95423e54f7a54decf60c7552f45b8b60407"

hash4 = "76efc8c64654d8f2318cc513c0aaf0da612423b1715e867b4622712ba0b3926f"

hash5 = "c3e2af892b813f3dcba4d0970489652d6f195b7985dc98f08eaddca7727786f0"

hash6 = "d7816ba6ddda0c4e833d9bba85864de6b1bd289246fcedae84b8a6581db3f5b6"

hash7 = "e93969a57ef2a7aee13a159cbf2015e2c8219d9153078e257b743d5cd90f05cb"

hash8 = "45984ae78d18332ecb33fe3371e5eb556c0db86f1d3ba8a835b72cd61a7eeecf"

id = "56685a0a-523d-4060-a008-aa28542cb85c"

malpedia_reference = "

$string1 = "LaunchConditionsValidateProductIDProcessComponentsUnpublishFeaturesRemoveFilesRegisterUserRegisterProductInstalled OR PhysicalMemory >= 2048" ascii

$string2 = ".cab" ascii $string3 = ".wav" ascii

$string4 = ".dll" ascii $supporting1 = ".raw" ascii

(uint32(0) == 0xe011cfd0) and filesize < 200000KB and all of ($string*) and 1 of ($supporting*)

(20250411 | Detects supporting file used by Octowave Loader containing hardcoded values)

author = "Jai Minton (@CyberRaiju) - HuntressLabs"

description = "Detects supporting file used by Octowave Loader containing hardcoded values"

license = "Detection Rule License 1.1

yt_reference = "

reference = "

hash1 = "C4CBAA7E4521FA0ED9CC634C5E2BACBF41F46842CA4526B7904D98843A7E9DB9"

hash2 = "F5CFB2E634539D5DC7FFE202FFDC422EF7457100401BA1FBC21DD05558719865"

hash3 = "56F1967F7177C166386D864807CDF03D5BBD3F118A285CE67EA226D02E5CF58C"

hash4 = "11EE5AD8A81AE85E5B7DDF93ADF6EDD20DE8460C755BF0426DFCBC7F658D7E85"

hash5 = "D218B65493E4D9D85CBC2F7B608F4F7E501708014BC04AF27D33D995AA54A703"

hash6 = "0C112F9DFE27211B357C74F358D9C144EA10CC0D92D6420B8742B72A65562C5A"

id = "56685a0a-523d-4060-a008-aa28542cb85c"

malpedia_reference = "

$unique_key = {1D 1C 1F 1E 01 01 03 02 05 04 07 06 09 D4 0E 0A 0D 0C 0F 0E 31 30 31 32 35 34 36 36 39 38 DC 3F 3D 3C 3E} // 1012546698 unknown unique identifier and surrounding bytes

$unique_string2 = "A@CBEDGFIHKJMLONqpsrutwvyx"

(uint16(0) != 0x5a4d) and filesize < 10000KB and all of them