Avast found this unidentified RAT, which abuses a code-signing certificate by the Philippine Navy. It is statically linked against OpenSSL 1.1.1g.
rule win_unidentified_091_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.unidentified_091." info = "autogenerated rule brought to you by yara-signator" tool = "yara-signator v0.6.0" signator_config = "callsandjumps;datarefs;binvalue" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.unidentified_091" malpedia_rule_date = "20260916" malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6" malpedia_version = "20260917" malpedia_license = "CC BY-SA 4.0" malpedia_sharing = "TLP:WHITE" /* DISCLAIMER * 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: * https://github.com/fxb-cocacoding/yara-signator * 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. */ strings: $sequence_0 = { 488d4101 480f43c1 498b4e28 4803f8 448bc9 483bf8 490f43db } // n = 7, score = 100 // 488d4101 | mov dword ptr [ebx + 0x7f8], eax // 480f43c1 | dec esp // 498b4e28 | mov eax, dword ptr [esp + 0x90] // 4803f8 | dec eax // 448bc9 | mov dword ptr [esp + 0x48], eax // 483bf8 | dec ebp // 490f43db | test eax, eax $sequence_1 = { c3 41b89d000000 488d1598910c00 488bcf e8???????? 488b7c2440 b801000000 } // n = 7, score = 100 // c3 | lea ecx, [0xa6121] // 41b89d000000 | dec eax // 488d1598910c00 | cmp ecx, eax // 488bcf | ja 0x1f6a // e8???????? | // 488b7c2440 | dec eax // b801000000 | cmp edi, ecx $sequence_2 = { 4c8bc6 e8???????? 41bcc0000000 0f1f00 4c8b842488000000 488d5310 488bcb } // n = 7, score = 100 // 4c8bc6 | mov al, 1 // e8???????? | // 41bcc0000000 | mov byte ptr [edi + 8], al // 0f1f00 | xor al, al // 4c8b842488000000 | inc ebp // 488d5310 | xor esp, esp // 488bcb | jmp 0xf3 $sequence_3 = { e8???????? 488b4b18 e8???????? 488b4b30 488d15788f1100 41b86b000000 e8???????? } // n = 7, score = 100 // e8???????? | // 488b4b18 | inc esp // e8???????? | // 488b4b30 | lea eax, [edx - 0x37] // 488d15788f1100 | dec eax // 41b86b000000 | test eax, eax // e8???????? | $sequence_4 = { d3e8 49895708 41894718 0fb60a 83e10f 4a0fbe840108841d00 428a8c0118841d00 } // n = 7, score = 100 // d3e8 | lea ecx, [0xa3cb3] // 49895708 | dec ebp // 41894718 | mov ecx, eax // 0fb60a | dec esp // 83e10f | sub ecx, ecx // 4a0fbe840108841d00 | mov edx, 4 // 428a8c0118841d00 | dec eax $sequence_5 = { 7433 498b54cd18 4d8bc6 488b4d18 e8???????? 4c8d05ab311200 85c0 } // n = 7, score = 100 // 7433 | mov eax, 0xffffffff // 498b54cd18 | inc ecx // 4d8bc6 | mov eax, 9 // 488b4d18 | test eax, eax // e8???????? | // 4c8d05ab311200 | jne 0x1a0b // 85c0 | dec eax $sequence_6 = { c1e017 0bc1 89442404 8bca c1e916 8bc2 83e11f } // n = 7, score = 100 // c1e017 | add edx, eax // 0bc1 | dec eax // 89442404 | xor ebx, edi // 8bca | dec eax // c1e916 | mov dword ptr [esp + 0x30], edi // 8bc2 | dec eax // 83e11f | mov edi, dword ptr [esp + 0x40] $sequence_7 = { 85c0 0f845f010000 4533c0 488d542440 488bce e8???????? 85c0 } // n = 7, score = 100 // 85c0 | inc esp // 0f845f010000 | mov ebx, esi // 4533c0 | xor edx, eax // 488d542440 | inc ebp // 488bce | xor ebx, edx // e8???????? | // 85c0 | inc ebp $sequence_8 = { 8d0c03 488b442448 803c0100 0f854b020000 c6040101 8b0c8f 3bce } // n = 7, score = 100 // 8d0c03 | mov eax, edx // 488b442448 | inc ebp // 803c0100 | mov eax, edx // 0f854b020000 | dec ecx // c6040101 | mov ecx, dword ptr [esi + 0x38] // 8b0c8f | dec eax // 3bce | add ebx, eax $sequence_9 = { 8b94b3b07b2500 448b848bb0772500 428b8c93b07f2500 42338c8bb0832500 4133c8 33ca 334c2420 } // n = 7, score = 100 // 8b94b3b07b2500 | mov dword ptr [esp + 0x20], edi // 448b848bb0772500 | dec ecx // 428b8c93b07f2500 | mov ecx, esp // 42338c8bb0832500 | cmp eax, -1 // 4133c8 | je 0xfbb // 33ca | inc ebp // 334c2420 | xor ecx, ecx condition: 7 of them and filesize < 5777408 }
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