OATBOAT is a loader that loads and executes shellcode payloads.
rule win_oatboat_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-01-05" version = "1" description = "Detects win.oatboat." 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.oatboat" malpedia_rule_date = "20260105" malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79" malpedia_version = "20251219" 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 = { c745e465655669 c745e872747561 c745ec6c4d656d c745f06f727900 e8???????? 41b900800000 } // n = 6, score = 100 // c745e465655669 | dec eax // c745e872747561 | lea edx, [ebp + 0x48] // c745ec6c4d656d | dec eax // c745f06f727900 | or ecx, 0xffffffff // e8???????? | // 41b900800000 | call eax $sequence_1 = { 488d0dc20b0000 ff15???????? 33c0 4883c450 415f } // n = 5, score = 100 // 488d0dc20b0000 | xor ebx, ebx // ff15???????? | // 33c0 | mov dword ptr [ebp - 0x1c], 0x4e0052 // 4883c450 | jne 0x9f // 415f | dec ecx $sequence_2 = { 4c896538 c745e04e74416c c745e46c6f6361 c745e874655669 c745ec72747561 c745f06c4d656d c745f46f727900 } // n = 7, score = 100 // 4c896538 | je 0x50 // c745e04e74416c | dec esp // c745e46c6f6361 | mov esi, edi // c745e874655669 | dec esp // c745ec72747561 | sub esi, ebx // c745f06c4d656d | movsx edx, byte ptr [ebx] // c745f46f727900 | movzx ecx, al $sequence_3 = { c745e8656d6f72 66c745ec7900 e8???????? 4d8bc4 } // n = 4, score = 100 // c745e8656d6f72 | mov esi, edi // 66c745ec7900 | dec ebp // e8???????? | // 4d8bc4 | test ebx, ebx $sequence_4 = { c745ec72747561 c745f06c4d656d c745f46f727900 e8???????? 4c8d4d38 c744242840000000 4533c0 } // n = 7, score = 100 // c745ec72747561 | dec eax // c745f06c4d656d | lea ecx, [0xbc2] // c745f46f727900 | inc edi // e8???????? | // 4c8d4d38 | movsx eax, byte ptr [edi + ebp] // c744242840000000 | lea ecx, [edx - 0x41] // 4533c0 | cmp ecx, 0x19 $sequence_5 = { 488bc8 e8???????? 488bd8 488b7c2458 488bc3 } // n = 5, score = 100 // 488bc8 | dec eax // e8???????? | // 488bd8 | sub esp, 0x40 // 488b7c2458 | dec eax // 488bc3 | mov edi, ecx $sequence_6 = { 7527 488d4df0 c745f04c6f6164 c745f44c696272 c745f861727957 44887dfc e8???????? } // n = 7, score = 100 // 7527 | dec ecx // 488d4df0 | add eax, ebx // c745f04c6f6164 | dec ecx // c745f44c696272 | add ecx, ebx // c745f861727957 | inc esp // 44887dfc | movzx eax, word ptr [edx + eax] // e8???????? | $sequence_7 = { c745ec33003200 c745f02e004400 c745f44c004c00 e8???????? } // n = 4, score = 100 // c745ec33003200 | dec ecx // c745f02e004400 | mov ecx, edi // c745f44c004c00 | call ebx // e8???????? | condition: 7 of them and filesize < 58368 }
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