Part of Mythic C2, written in Nim. Considered deprecated, as it is only compatible with Mythic 2.1.
rule win_nimplant_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-12-06" version = "1" description = "Detects win.nimplant." 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.nimplant" malpedia_rule_date = "20231130" malpedia_hash = "fc8a0e9f343f6d6ded9e7df1a64dac0cc68d7351" malpedia_version = "20230808" 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 = { 4c89e9 0f11642440 e8???????? 803b00 0f8515ffffff 488b4c2468 4885c9 } // n = 7, score = 100 // 4c89e9 | add edx, edx // 0f11642440 | dec eax // e8???????? | // 803b00 | add eax, 3 // 0f8515ffffff | dec eax // 488b4c2468 | cmp ecx, edx // 4885c9 | dec esp $sequence_1 = { 894c2430 4889ac24b0000000 e9???????? 4981ffff7f0000 4c89f2 488b4b08 490f4ed7 } // n = 7, score = 100 // 894c2430 | dec eax // 4889ac24b0000000 | lea eax, [0x589ec] // e9???????? | // 4981ffff7f0000 | dec eax // 4c89f2 | mov dword ptr [ecx + 0x18], 0x24 // 488b4b08 | dec eax // 490f4ed7 | mov dword ptr [ecx + 0x20], eax $sequence_2 = { 488d051e3a0800 48895110 48894120 48c741183a000000 48c7410800000000 48c7442420a1060000 e8???????? } // n = 7, score = 100 // 488d051e3a0800 | test ebp, ebp // 48895110 | jne 0xfc6 // 48894120 | inc ecx // 48c741183a000000 | mov eax, 0x4909bf2b // 48c7410800000000 | dec esp // 48c7442420a1060000 | mov edx, ebp // e8???????? | $sequence_3 = { e8???????? 488b442440 488b542448 44886c0208 4883c001 0f8093040000 488b542448 } // n = 7, score = 100 // e8???????? | // 488b442440 | sub esp, 0x1d8 // 488b542448 | inc ecx // 44886c0208 | mov eax, 0x7f2bfd03 // 4883c001 | push ebp // 0f8093040000 | push edi // 488b542448 | push esi $sequence_4 = { e8???????? 4c8b442430 48ba0000000000000040 4889f1 4c01e9 0f80b1000000 4885c9 } // n = 7, score = 100 // e8???????? | // 4c8b442430 | por mm2, mm4 // 48ba0000000000000040 | por xmm3, xmm2 // 4889f1 | inc ecx // 4c01e9 | movq mm2, mm5 // 0f80b1000000 | inc esp // 4885c9 | movq mm4, mm3 $sequence_5 = { f30f6f25???????? 4889ea 41b8a94d975e 4c89e9 4c899c2408010000 4c89942400010000 0f11a42410010000 } // n = 7, score = 100 // f30f6f25???????? | // 4889ea | mov edx, dword ptr [esp + 0x40] // 41b8a94d975e | dec eax // 4c89e9 | mov eax, dword ptr [esp + 0x48] // 4c899c2408010000 | dec eax // 4c89942400010000 | test edx, edx // 0f11a42410010000 | dec eax $sequence_6 = { 488b9424f0000000 4889d1 4883e904 0f80de0f0000 4839ca 0f8e58100000 4885c9 } // n = 7, score = 100 // 488b9424f0000000 | add byte ptr [eax + 0x48], al // 4889d1 | test dword ptr [ecx], eax // 4883e904 | je 0x350 // 0f80de0f0000 | dec eax // 4839ca | mov ecx, dword ptr [esp + 0x98] // 0f8e58100000 | dec eax // 4885c9 | test ecx, ecx $sequence_7 = { e8???????? 803b00 488b942488000000 488b842480000000 0f8599feffff 4c8b4e58 4c89f1 } // n = 7, score = 100 // e8???????? | // 803b00 | dec esp // 488b942488000000 | mov ecx, esp // 488b842480000000 | je 0x1a7 // 0f8599feffff | dec eax // 4c8b4e58 | test dword ptr [ebp], edi // 4c89f1 | je 0x4ca $sequence_8 = { 80f90b 0f873b1a0000 0fb6f2 83ee01 4863f6 4883c60c 48c1e604 } // n = 7, score = 100 // 80f90b | mov edx, esi // 0f873b1a0000 | dec esp // 0fb6f2 | mov eax, dword ptr [esp + 0x78] // 83ee01 | mov edx, 1 // 4863f6 | dec eax // 4883c60c | mov eax, dword ptr [ecx] // 48c1e604 | call dword ptr [eax + 0x18] $sequence_9 = { 4889eb 48897c2440 488b7c2438 4889c5 4c89ee 4c897c2460 } // n = 6, score = 100 // 4889eb | mov ecx, eax // 48897c2440 | movzx esi, byte ptr [ebx] // 488b7c2438 | dec eax // 4889c5 | mov dword ptr [esp + 0x78], eax // 4c89ee | inc eax // 4c897c2460 | test dh, dh condition: 7 of them and filesize < 1811456 }
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