Actor(s): DarkHotel
There is no description at this point.
rule win_ramsay_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.ramsay." 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.ramsay" 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 = { ff15???????? 85c0 7502 eb02 ebb1 } // n = 5, score = 600 // ff15???????? | // 85c0 | test eax, eax // 7502 | jne 4 // eb02 | jmp 4 // ebb1 | jmp 0xffffffb3 $sequence_1 = { 83f820 7502 eb07 33c0 } // n = 4, score = 600 // 83f820 | cmp eax, 0x20 // 7502 | jne 4 // eb07 | jmp 9 // 33c0 | xor eax, eax $sequence_2 = { 85c0 7514 ff15???????? 83f820 } // n = 4, score = 600 // 85c0 | test eax, eax // 7514 | jne 0x16 // ff15???????? | // 83f820 | cmp eax, 0x20 $sequence_3 = { 0fb611 81fae9000000 7404 33c0 } // n = 4, score = 500 // 0fb611 | movzx edx, byte ptr [ecx] // 81fae9000000 | cmp edx, 0xe9 // 7404 | je 6 // 33c0 | xor eax, eax $sequence_4 = { 8b45fc 8945f0 8b4df0 0fb611 81fae9000000 } // n = 5, score = 500 // 8b45fc | mov eax, dword ptr [ebp - 4] // 8945f0 | mov dword ptr [ebp - 0x10], eax // 8b4df0 | mov ecx, dword ptr [ebp - 0x10] // 0fb611 | movzx edx, byte ptr [ecx] // 81fae9000000 | cmp edx, 0xe9 $sequence_5 = { 83c001 8945fc 8b4dfc 3b4d08 732c e8???????? 33d2 } // n = 7, score = 500 // 83c001 | add eax, 1 // 8945fc | mov dword ptr [ebp - 4], eax // 8b4dfc | mov ecx, dword ptr [ebp - 4] // 3b4d08 | cmp ecx, dword ptr [ebp + 8] // 732c | jae 0x2e // e8???????? | // 33d2 | xor edx, edx $sequence_6 = { 732c e8???????? 33d2 b93e000000 f7f1 8955f4 } // n = 6, score = 500 // 732c | jae 0x2e // e8???????? | // 33d2 | xor edx, edx // b93e000000 | mov ecx, 0x3e // f7f1 | div ecx // 8955f4 | mov dword ptr [ebp - 0xc], edx $sequence_7 = { 8d45f0 50 8d4de5 51 e8???????? 83c40c 6a05 } // n = 7, score = 500 // 8d45f0 | lea eax, [ebp - 0x10] // 50 | push eax // 8d4de5 | lea ecx, [ebp - 0x1b] // 51 | push ecx // e8???????? | // 83c40c | add esp, 0xc // 6a05 | push 5 $sequence_8 = { ff15???????? 85c0 7504 33c0 eb63 6a05 8b45fc } // n = 7, score = 500 // ff15???????? | // 85c0 | test eax, eax // 7504 | jne 6 // 33c0 | xor eax, eax // eb63 | jmp 0x65 // 6a05 | push 5 // 8b45fc | mov eax, dword ptr [ebp - 4] $sequence_9 = { 8955ec 8b5508 0355e8 8b45ec } // n = 4, score = 500 // 8955ec | mov dword ptr [ebp - 0x14], edx // 8b5508 | mov edx, dword ptr [ebp + 8] // 0355e8 | add edx, dword ptr [ebp - 0x18] // 8b45ec | mov eax, dword ptr [ebp - 0x14] $sequence_10 = { 8945ec c745fc00000000 c745f400000000 c745f000000000 c645e4e9 c645e500 } // n = 6, score = 500 // 8945ec | mov dword ptr [ebp - 0x14], eax // c745fc00000000 | mov dword ptr [ebp - 4], 0 // c745f400000000 | mov dword ptr [ebp - 0xc], 0 // c745f000000000 | mov dword ptr [ebp - 0x10], 0 // c645e4e9 | mov byte ptr [ebp - 0x1c], 0xe9 // c645e500 | mov byte ptr [ebp - 0x1b], 0 $sequence_11 = { ff15???????? 33c0 e9???????? e8???????? 85c0 7507 } // n = 6, score = 400 // ff15???????? | // 33c0 | xor eax, eax // e9???????? | // e8???????? | // 85c0 | test eax, eax // 7507 | jne 9 $sequence_12 = { e8???????? c744243400000000 488b8424d0010000 48898424e8010000 } // n = 4, score = 200 // e8???????? | // c744243400000000 | test eax, eax // 488b8424d0010000 | jne 0xd // 48898424e8010000 | mov dword ptr [esp + 0x30], 0x11c $sequence_13 = { e8???????? c74424301c010000 488d4c2430 ff15???????? 85c0 } // n = 5, score = 200 // e8???????? | // c74424301c010000 | dec eax // 488d4c2430 | lea eax, [esp + 0x42] // ff15???????? | // 85c0 | dec eax $sequence_14 = { e8???????? c744244006000000 ff15???????? ba01000000 } // n = 4, score = 200 // e8???????? | // c744244006000000 | dec eax // ff15???????? | // ba01000000 | cmp dword ptr [esp + 0x1e8], 0 $sequence_15 = { e8???????? c744242801000000 33c0 6689442440 488d442442 } // n = 5, score = 200 // e8???????? | // c744242801000000 | mov dword ptr [esp + 0x28], 1 // 33c0 | xor eax, eax // 6689442440 | mov word ptr [esp + 0x40], ax // 488d442442 | dec eax condition: 7 of them and filesize < 2031616 }
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