Ransomware.
rule win_rhino_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.rhino." 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.rhino" 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 = { 0c80 57 88442418 8b4500 56 51 8bcd } // n = 7, score = 400 // 0c80 | or al, 0x80 // 57 | push edi // 88442418 | mov byte ptr [esp + 0x18], al // 8b4500 | mov eax, dword ptr [ebp] // 56 | push esi // 51 | push ecx // 8bcd | mov ecx, ebp $sequence_1 = { 8945fc 8d45d0 50 e8???????? e8???????? c20400 6a00 } // n = 7, score = 400 // 8945fc | mov dword ptr [ebp - 4], eax // 8d45d0 | lea eax, [ebp - 0x30] // 50 | push eax // e8???????? | // e8???????? | // c20400 | ret 4 // 6a00 | push 0 $sequence_2 = { 7202 8bc1 8b00 c3 8b4c2404 3b4c2408 7413 } // n = 7, score = 400 // 7202 | jb 4 // 8bc1 | mov eax, ecx // 8b00 | mov eax, dword ptr [eax] // c3 | ret // 8b4c2404 | mov ecx, dword ptr [esp + 4] // 3b4c2408 | cmp ecx, dword ptr [esp + 8] // 7413 | je 0x15 $sequence_3 = { 8bc2 f7d8 3bc6 7334 68???????? 8d4dd8 e8???????? } // n = 7, score = 400 // 8bc2 | mov eax, edx // f7d8 | neg eax // 3bc6 | cmp eax, esi // 7334 | jae 0x36 // 68???????? | // 8d4dd8 | lea ecx, [ebp - 0x28] // e8???????? | $sequence_4 = { 6a00 68???????? ff75d4 ffd6 ff75d4 ff15???????? 68e8030000 } // n = 7, score = 400 // 6a00 | push 0 // 68???????? | // ff75d4 | push dword ptr [ebp - 0x2c] // ffd6 | call esi // ff75d4 | push dword ptr [ebp - 0x2c] // ff15???????? | // 68e8030000 | push 0x3e8 $sequence_5 = { 5e c9 c20400 b8???????? e8???????? 81ec94000000 53 } // n = 7, score = 400 // 5e | pop esi // c9 | leave // c20400 | ret 4 // b8???????? | // e8???????? | // 81ec94000000 | sub esp, 0x94 // 53 | push ebx $sequence_6 = { 8b4b04 194804 8bc6 5e 5b 8be5 } // n = 6, score = 400 // 8b4b04 | mov ecx, dword ptr [ebx + 4] // 194804 | sbb dword ptr [eax + 4], ecx // 8bc6 | mov eax, esi // 5e | pop esi // 5b | pop ebx // 8be5 | mov esp, ebp $sequence_7 = { 55 56 55 e8???????? 83c430 8bcf c1e105 } // n = 7, score = 400 // 55 | push ebp // 56 | push esi // 55 | push ebp // e8???????? | // 83c430 | add esp, 0x30 // 8bcf | mov ecx, edi // c1e105 | shl ecx, 5 $sequence_8 = { 57 8b4104 8bd0 8b39 2bd7 8b4c2410 8b7104 } // n = 7, score = 400 // 57 | push edi // 8b4104 | mov eax, dword ptr [ecx + 4] // 8bd0 | mov edx, eax // 8b39 | mov edi, dword ptr [ecx] // 2bd7 | sub edx, edi // 8b4c2410 | mov ecx, dword ptr [esp + 0x10] // 8b7104 | mov esi, dword ptr [ecx + 4] $sequence_9 = { 8b4d08 33c0 83ec40 0f57e4 837d1401 660f6e4110 660f6ec8 } // n = 7, score = 400 // 8b4d08 | mov ecx, dword ptr [ebp + 8] // 33c0 | xor eax, eax // 83ec40 | sub esp, 0x40 // 0f57e4 | xorps xmm4, xmm4 // 837d1401 | cmp dword ptr [ebp + 0x14], 1 // 660f6e4110 | movd xmm0, dword ptr [ecx + 0x10] // 660f6ec8 | movd xmm1, eax condition: 7 of them and filesize < 1288192 }
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