There is no description at this point.
rule win_fobber_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2024-10-31" version = "1" description = "Detects win.fobber." 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.fobber" malpedia_rule_date = "20241030" malpedia_hash = "26e26953c49c8efafbf72a38076855d578e0a2e4" malpedia_version = "20241030" 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 = { 8b5508 8b4d0c 3002 c0c803 } // n = 4, score = 1100 // 8b5508 | mov edx, dword ptr [ebp + 8] // 8b4d0c | mov ecx, dword ptr [ebp + 0xc] // 3002 | xor byte ptr [edx], al // c0c803 | ror al, 3 $sequence_1 = { 57 e8???????? 85c0 740f 89c1 8b450c fc } // n = 7, score = 1100 // 57 | push edi // e8???????? | // 85c0 | test eax, eax // 740f | je 0x11 // 89c1 | mov ecx, eax // 8b450c | mov eax, dword ptr [ebp + 0xc] // fc | cld $sequence_2 = { 660fc146f9 6685c0 7515 0fb646f8 50 0fb746f6 } // n = 6, score = 1100 // 660fc146f9 | xadd word ptr [esi - 7], ax // 6685c0 | test ax, ax // 7515 | jne 0x17 // 0fb646f8 | movzx eax, byte ptr [esi - 8] // 50 | push eax // 0fb746f6 | movzx eax, word ptr [esi - 0xa] $sequence_3 = { 8d4d08 51 ff31 ffd0 85c0 7403 8b4508 } // n = 7, score = 1100 // 8d4d08 | lea ecx, [ebp + 8] // 51 | push ecx // ff31 | push dword ptr [ecx] // ffd0 | call eax // 85c0 | test eax, eax // 7403 | je 5 // 8b4508 | mov eax, dword ptr [ebp + 8] $sequence_4 = { 55 89e5 51 57 8b7d08 57 } // n = 6, score = 1100 // 55 | push ebp // 89e5 | mov ebp, esp // 51 | push ecx // 57 | push edi // 8b7d08 | mov edi, dword ptr [ebp + 8] // 57 | push edi $sequence_5 = { 31c9 f7d1 fc f2ae f7d1 } // n = 5, score = 1100 // 31c9 | xor ecx, ecx // f7d1 | not ecx // fc | cld // f2ae | repne scasb al, byte ptr es:[edi] // f7d1 | not ecx $sequence_6 = { 55 89e5 31c0 50 50 ff750c ff7508 } // n = 7, score = 1100 // 55 | push ebp // 89e5 | mov ebp, esp // 31c0 | xor eax, eax // 50 | push eax // 50 | push eax // ff750c | push dword ptr [ebp + 0xc] // ff7508 | push dword ptr [ebp + 8] $sequence_7 = { 3002 c0c803 0453 42 } // n = 4, score = 1100 // 3002 | xor byte ptr [edx], al // c0c803 | ror al, 3 // 0453 | add al, 0x53 // 42 | inc edx $sequence_8 = { 0485 40 47 c9 7283 e61f } // n = 6, score = 100 // 0485 | add al, 0x85 // 40 | inc eax // 47 | inc edi // c9 | leave // 7283 | jb 0xffffff85 // e61f | out 0x1f, al $sequence_9 = { 028736c8f07c 7d41 6f 01e9 } // n = 4, score = 100 // 028736c8f07c | add al, byte ptr [edi + 0x7cf0c836] // 7d41 | jge 0x43 // 6f | outsd dx, dword ptr [esi] // 01e9 | add ecx, ebp $sequence_10 = { 4a bdb098f55a 6798 5b 348d 5a } // n = 6, score = 100 // 4a | dec edx // bdb098f55a | mov ebp, 0x5af598b0 // 6798 | cwde // 5b | pop ebx // 348d | xor al, 0x8d // 5a | pop edx $sequence_11 = { 81c112500000 81c1d6530000 81e951b50000 81e9a88bffff 81c17d5b0000 } // n = 5, score = 100 // 81c112500000 | add ecx, 0x5012 // 81c1d6530000 | add ecx, 0x53d6 // 81e951b50000 | sub ecx, 0xb551 // 81e9a88bffff | sub ecx, 0xffff8ba8 // 81c17d5b0000 | add ecx, 0x5b7d $sequence_12 = { 8bec a1???????? 80383f 7414 6a00 } // n = 5, score = 100 // 8bec | mov ebp, esp // a1???????? | // 80383f | cmp byte ptr [eax], 0x3f // 7414 | je 0x16 // 6a00 | push 0 $sequence_13 = { df9c6182a5b1b2 e8???????? 54 e437 d3766f fa 42 } // n = 7, score = 100 // df9c6182a5b1b2 | fistp word ptr [ecx - 0x4d4e5a7e] // e8???????? | // 54 | push esp // e437 | in al, 0x37 // d3766f | sal dword ptr [esi + 0x6f], cl // fa | cli // 42 | inc edx $sequence_14 = { d470 44 b200 4f } // n = 4, score = 100 // d470 | aam 0x70 // 44 | inc esp // b200 | mov dl, 0 // 4f | dec edi $sequence_15 = { 8d46ff 0f85196e0100 807dfc00 7407 8b4df8 836170fd 5e } // n = 7, score = 100 // 8d46ff | lea eax, [esi - 1] // 0f85196e0100 | jne 0x16e1f // 807dfc00 | cmp byte ptr [ebp - 4], 0 // 7407 | je 9 // 8b4df8 | mov ecx, dword ptr [ebp - 8] // 836170fd | and dword ptr [ecx + 0x70], 0xfffffffd // 5e | pop esi condition: 7 of them and filesize < 188416 }
If your designated proposal does not fit in any other category, feel free to write a free-text in the comment field below. Changes regarding references should be proposed on the Malpedia library page.
Your suggestion will be reviewed before being published. Thank you for contributing!
YYYY-MM-DD
YYYY-MM
YYYY