Actor(s): TA428
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rule win_ncctrojan_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.ncctrojan." 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.ncctrojan" malpedia_rule_date = "20230124" malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686" malpedia_version = "20230125" 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 = { 68???????? e9???????? 83f801 750a 68???????? e9???????? } // n = 6, score = 500 // 68???????? | // e9???????? | // 83f801 | cmp eax, 1 // 750a | jne 0xc // 68???????? | // e9???????? | $sequence_1 = { 83f805 7536 8b85e8feffff 85c0 750a } // n = 5, score = 500 // 83f805 | cmp eax, 5 // 7536 | jne 0x38 // 8b85e8feffff | mov eax, dword ptr [ebp - 0x118] // 85c0 | test eax, eax // 750a | jne 0xc $sequence_2 = { 0f280d???????? 8bfe 2bf9 8d4a10 0f1f840000000000 } // n = 5, score = 400 // 0f280d???????? | // 8bfe | mov edi, esi // 2bf9 | sub edi, ecx // 8d4a10 | lea ecx, [edx + 0x10] // 0f1f840000000000 | nop dword ptr [eax + eax] $sequence_3 = { e8???????? 8bf0 8bfa eb10 } // n = 4, score = 400 // e8???????? | // 8bf0 | mov esi, eax // 8bfa | mov edi, edx // eb10 | jmp 0x12 $sequence_4 = { e8???????? 83c40c 66c745f40000 8d45ec 0f57c0 } // n = 5, score = 400 // e8???????? | // 83c40c | add esp, 0xc // 66c745f40000 | mov word ptr [ebp - 0xc], 0 // 8d45ec | lea eax, [ebp - 0x14] // 0f57c0 | xorps xmm0, xmm0 $sequence_5 = { 8b0d???????? e9???????? 833d????????01 0f8581010000 ff35???????? 8d44242c 68???????? } // n = 7, score = 400 // 8b0d???????? | // e9???????? | // 833d????????01 | // 0f8581010000 | jne 0x187 // ff35???????? | // 8d44242c | lea eax, [esp + 0x2c] // 68???????? | $sequence_6 = { e8???????? 68???????? 8d85f0bfffff 6800400000 50 e8???????? 68???????? } // n = 7, score = 400 // e8???????? | // 68???????? | // 8d85f0bfffff | lea eax, [ebp - 0x4010] // 6800400000 | push 0x4000 // 50 | push eax // e8???????? | // 68???????? | $sequence_7 = { 8d8424bc080000 6a00 50 e8???????? 83c41c } // n = 5, score = 400 // 8d8424bc080000 | lea eax, [esp + 0x8bc] // 6a00 | push 0 // 50 | push eax // e8???????? | // 83c41c | add esp, 0x1c $sequence_8 = { 50 e8???????? 8b85ccfeffff 6a10 } // n = 4, score = 300 // 50 | push eax // e8???????? | // 8b85ccfeffff | mov eax, dword ptr [ebp - 0x134] // 6a10 | push 0x10 $sequence_9 = { 8b450c 3dffffff7f 7605 e9???????? } // n = 4, score = 300 // 8b450c | mov eax, dword ptr [ebp + 0xc] // 3dffffff7f | cmp eax, 0x7fffffff // 7605 | jbe 7 // e9???????? | $sequence_10 = { 0f84b8000000 6a14 59 8bf3 } // n = 4, score = 300 // 0f84b8000000 | je 0xbe // 6a14 | push 0x14 // 59 | pop ecx // 8bf3 | mov esi, ebx $sequence_11 = { 50 ff75c8 8d4708 ff75c4 } // n = 4, score = 300 // 50 | push eax // ff75c8 | push dword ptr [ebp - 0x38] // 8d4708 | lea eax, [edi + 8] // ff75c4 | push dword ptr [ebp - 0x3c] $sequence_12 = { 50 53 e8???????? 59 59 5b c7461407000000 } // n = 7, score = 300 // 50 | push eax // 53 | push ebx // e8???????? | // 59 | pop ecx // 59 | pop ecx // 5b | pop ebx // c7461407000000 | mov dword ptr [esi + 0x14], 7 $sequence_13 = { 0f8433110000 83ec08 0fae5c2404 8b442404 25807f0000 } // n = 5, score = 300 // 0f8433110000 | je 0x1139 // 83ec08 | sub esp, 8 // 0fae5c2404 | stmxcsr dword ptr [esp + 4] // 8b442404 | mov eax, dword ptr [esp + 4] // 25807f0000 | and eax, 0x7f80 $sequence_14 = { 85f6 0f99c0 8d044501000000 5e 5d c3 3b0d???????? } // n = 7, score = 300 // 85f6 | test esi, esi // 0f99c0 | setns al // 8d044501000000 | lea eax, [eax*2 + 1] // 5e | pop esi // 5d | pop ebp // c3 | ret // 3b0d???????? | $sequence_15 = { 7404 c60330 43 ffb57cffffff } // n = 4, score = 300 // 7404 | je 6 // c60330 | mov byte ptr [ebx], 0x30 // 43 | inc ebx // ffb57cffffff | push dword ptr [ebp - 0x84] condition: 7 of them and filesize < 1160192 }
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