Ransomware, potential rebranding of win.sfile.
rule win_mindware_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.mindware." 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.mindware" 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 = { c745f4f09b4300 eb1a 33c9 7409 c745f8???????? eb07 c745f8???????? } // n = 7, score = 100 // c745f4f09b4300 | mov dword ptr [ebp - 0xc], 0x439bf0 // eb1a | jmp 0x1c // 33c9 | xor ecx, ecx // 7409 | je 0xb // c745f8???????? | // eb07 | jmp 9 // c745f8???????? | $sequence_1 = { c78528ffffffd8034400 c7852cffffffe0034400 c78530ffffffe8034400 c78534fffffff8034400 c78538ffffff08044400 c7853cffffff10044400 c78540ffffff18044400 } // n = 7, score = 100 // c78528ffffffd8034400 | mov dword ptr [ebp - 0xd8], 0x4403d8 // c7852cffffffe0034400 | mov dword ptr [ebp - 0xd4], 0x4403e0 // c78530ffffffe8034400 | mov dword ptr [ebp - 0xd0], 0x4403e8 // c78534fffffff8034400 | mov dword ptr [ebp - 0xcc], 0x4403f8 // c78538ffffff08044400 | mov dword ptr [ebp - 0xc8], 0x440408 // c7853cffffff10044400 | mov dword ptr [ebp - 0xc4], 0x440410 // c78540ffffff18044400 | mov dword ptr [ebp - 0xc0], 0x440418 $sequence_2 = { c785b4feffff88024400 c785b8feffff90024400 c785bcfeffff98024400 c785c0feffffa0024400 c785c4feffffa8024400 c785c8feffffb0024400 } // n = 6, score = 100 // c785b4feffff88024400 | mov dword ptr [ebp - 0x14c], 0x440288 // c785b8feffff90024400 | mov dword ptr [ebp - 0x148], 0x440290 // c785bcfeffff98024400 | mov dword ptr [ebp - 0x144], 0x440298 // c785c0feffffa0024400 | mov dword ptr [ebp - 0x140], 0x4402a0 // c785c4feffffa8024400 | mov dword ptr [ebp - 0x13c], 0x4402a8 // c785c8feffffb0024400 | mov dword ptr [ebp - 0x138], 0x4402b0 $sequence_3 = { 740a 8b4dc0 51 ff15???????? 33c0 e9???????? } // n = 6, score = 100 // 740a | je 0xc // 8b4dc0 | mov ecx, dword ptr [ebp - 0x40] // 51 | push ecx // ff15???????? | // 33c0 | xor eax, eax // e9???????? | $sequence_4 = { 33148dc0bc4400 8bcb c1e918 33148dc0c44400 8b4df0 } // n = 5, score = 100 // 33148dc0bc4400 | xor edx, dword ptr [ecx*4 + 0x44bcc0] // 8bcb | mov ecx, ebx // c1e918 | shr ecx, 0x18 // 33148dc0c44400 | xor edx, dword ptr [ecx*4 + 0x44c4c0] // 8b4df0 | mov ecx, dword ptr [ebp - 0x10] $sequence_5 = { 8b4508 83c02c 8945cc 6880000000 6a00 8d8d4cffffff 51 } // n = 7, score = 100 // 8b4508 | mov eax, dword ptr [ebp + 8] // 83c02c | add eax, 0x2c // 8945cc | mov dword ptr [ebp - 0x34], eax // 6880000000 | push 0x80 // 6a00 | push 0 // 8d8d4cffffff | lea ecx, [ebp - 0xb4] // 51 | push ecx $sequence_6 = { 83c002 8945e8 8b4df4 668b11 668955fe 8345f402 66837dfe00 } // n = 7, score = 100 // 83c002 | add eax, 2 // 8945e8 | mov dword ptr [ebp - 0x18], eax // 8b4df4 | mov ecx, dword ptr [ebp - 0xc] // 668b11 | mov dx, word ptr [ecx] // 668955fe | mov word ptr [ebp - 2], dx // 8345f402 | add dword ptr [ebp - 0xc], 2 // 66837dfe00 | cmp word ptr [ebp - 2], 0 $sequence_7 = { c78574e5ffffb8c34300 c78578e5ffffc0c34300 c7857ce5ffffc8c34300 c78580e5ffffd4c34300 c78584e5ffffe0c34300 c78588e5ffffe8c34300 } // n = 6, score = 100 // c78574e5ffffb8c34300 | mov dword ptr [ebp - 0x1a8c], 0x43c3b8 // c78578e5ffffc0c34300 | mov dword ptr [ebp - 0x1a88], 0x43c3c0 // c7857ce5ffffc8c34300 | mov dword ptr [ebp - 0x1a84], 0x43c3c8 // c78580e5ffffd4c34300 | mov dword ptr [ebp - 0x1a80], 0x43c3d4 // c78584e5ffffe0c34300 | mov dword ptr [ebp - 0x1a7c], 0x43c3e0 // c78588e5ffffe8c34300 | mov dword ptr [ebp - 0x1a78], 0x43c3e8 $sequence_8 = { 0fb6c9 33148dc0c84400 8bcb 33500c c1e910 } // n = 5, score = 100 // 0fb6c9 | movzx ecx, cl // 33148dc0c84400 | xor edx, dword ptr [ecx*4 + 0x44c8c0] // 8bcb | mov ecx, ebx // 33500c | xor edx, dword ptr [eax + 0xc] // c1e910 | shr ecx, 0x10 $sequence_9 = { 83c201 8955fc 837dfc04 7d12 8b45fc 8b4d08 8b1481 } // n = 7, score = 100 // 83c201 | add edx, 1 // 8955fc | mov dword ptr [ebp - 4], edx // 837dfc04 | cmp dword ptr [ebp - 4], 4 // 7d12 | jge 0x14 // 8b45fc | mov eax, dword ptr [ebp - 4] // 8b4d08 | mov ecx, dword ptr [ebp + 8] // 8b1481 | mov edx, dword ptr [ecx + eax*4] condition: 7 of them and filesize < 661504 }
If your designated proposal does not fit in any other category, feel free to write a free-text in the comment field below.
Please propose all changes regarding references on the Malpedia library page
Your suggestion will be reviewed before being published. Thank you for contributing!
YYYY-MM-DD
YYYY-MM
YYYY