Actor(s): Equation Group
FancyFilter is a piece of code that documents code overlap between frameworks used by Regin and Equation Group.
rule win_fancyfilter_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2024-10-31" version = "1" description = "Detects win.fancyfilter." 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.fancyfilter" 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 = { 85c0 740a 66833800 7404 b001 eb02 } // n = 6, score = 400 // 85c0 | test eax, eax // 740a | je 0xc // 66833800 | cmp word ptr [eax], 0 // 7404 | je 6 // b001 | mov al, 1 // eb02 | jmp 4 $sequence_1 = { 891d???????? 891d???????? b001 5b } // n = 4, score = 400 // 891d???????? | // 891d???????? | // b001 | mov al, 1 // 5b | pop ebx $sequence_2 = { 740a 66833800 7404 b001 eb02 } // n = 5, score = 400 // 740a | je 0xc // 66833800 | cmp word ptr [eax], 0 // 7404 | je 6 // b001 | mov al, 1 // eb02 | jmp 4 $sequence_3 = { 750d 8b472c a801 7406 } // n = 4, score = 400 // 750d | jne 0xf // 8b472c | mov eax, dword ptr [edi + 0x2c] // a801 | test al, 1 // 7406 | je 8 $sequence_4 = { a1???????? 83c012 50 ff15???????? a1???????? } // n = 5, score = 400 // a1???????? | // 83c012 | add eax, 0x12 // 50 | push eax // ff15???????? | // a1???????? | $sequence_5 = { 8d4f20 51 50 ff15???????? } // n = 4, score = 400 // 8d4f20 | lea ecx, [edi + 0x20] // 51 | push ecx // 50 | push eax // ff15???????? | $sequence_6 = { 85c0 740a 66833800 7404 b001 eb02 32c0 } // n = 7, score = 400 // 85c0 | test eax, eax // 740a | je 0xc // 66833800 | cmp word ptr [eax], 0 // 7404 | je 6 // b001 | mov al, 1 // eb02 | jmp 4 // 32c0 | xor al, al $sequence_7 = { 8b07 83e810 50 83c610 } // n = 4, score = 400 // 8b07 | mov eax, dword ptr [edi] // 83e810 | sub eax, 0x10 // 50 | push eax // 83c610 | add esi, 0x10 $sequence_8 = { 85c0 750d 8b472c a801 } // n = 4, score = 400 // 85c0 | test eax, eax // 750d | jne 0xf // 8b472c | mov eax, dword ptr [edi + 0x2c] // a801 | test al, 1 $sequence_9 = { 85c0 750d 8b472c a801 7406 } // n = 5, score = 400 // 85c0 | test eax, eax // 750d | jne 0xf // 8b472c | mov eax, dword ptr [edi + 0x2c] // a801 | test al, 1 // 7406 | je 8 condition: 7 of them and filesize < 169984 }
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