Actor(s): APT28
Suspected Zebrocy loader written in Nim.
rule win_unidentified_078_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.unidentified_078." 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.unidentified_078" malpedia_rule_date = "20260916" malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6" malpedia_version = "20260917" 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 = { 0f8412010000 0f8cee000000 80fa0d 0f8421010000 80fa1b 0f8576010000 } // n = 6, score = 200 // 0f8412010000 | dec eax // 0f8cee000000 | mov dword ptr [esp + 0x30], eax // 80fa0d | jmp 0xe65 // 0f8421010000 | mov edx, 2 // 80fa1b | dec eax // 0f8576010000 | mov ecx, ebx $sequence_1 = { 0f849a000000 f6420901 0f8590000000 8a4a08 80f91c 0f8784000000 b801000000 } // n = 7, score = 200 // 0f849a000000 | dec esp // f6420901 | mov ebp, dword ptr [ebp] // 0f8590000000 | dec esp // 8a4a08 | lea esi, [0xc716] // 80f91c | xor edi, edi // 0f8784000000 | dec esp // b801000000 | lea esp, [0xc6dd] $sequence_2 = { 8a441310 3c5c 7404 3c2f } // n = 4, score = 200 // 8a441310 | inc esp // 3c5c | add eax, dword ptr [ecx + 8] // 7404 | mov eax, edx // 3c2f | je 0x2b $sequence_3 = { 83eb5b 83fb01 0f8720010000 eb0f b901003b00 } // n = 5, score = 200 // 83eb5b | cmp dword ptr [edi + 8], 0x3f000000 // 83fb01 | jle 0x52f // 0f8720010000 | dec eax // eb0f | mov edx, edi // b901003b00 | dec eax $sequence_4 = { 3c18 0f8483000000 3c1c 740d 3c16 } // n = 5, score = 200 // 3c18 | mov ebx, dword ptr [esi + 8] // 0f8483000000 | dec eax // 3c1c | mov ecx, dword ptr [esp + 0x38] // 740d | je 0x224 // 3c16 | dec eax $sequence_5 = { b901010000 ff15???????? 85c0 740e } // n = 4, score = 200 // b901010000 | dec eax // ff15???????? | // 85c0 | mov ecx, dword ptr [edi + ebx] // 740e | lea ebp, [0x22528] $sequence_6 = { 80fa28 0f8d94010000 80fa26 0f8f18010000 80fa23 } // n = 5, score = 200 // 80fa28 | dec esp // 0f8d94010000 | mov ecx, edi // 80fa26 | cmp word ptr [ebp + 2], 0 // 0f8f18010000 | dec esp // 80fa23 | lea edi, [ebp + 2] $sequence_7 = { 83fb11 743f 81fba2000000 7437 89da 83e2fd } // n = 6, score = 200 // 83fb11 | dec edi // 743f | lea edx, [eax + ecx - 0x38] // 81fba2000000 | dec ebp // 7437 | mov ebx, dword ptr [edx] // 89da | dec ecx // 83e2fd | ja 0x31a $sequence_8 = { e9???????? 80fa0c 0f8412010000 0f8cee000000 80fa0d } // n = 5, score = 200 // e9???????? | // 80fa0c | dec eax // 0f8412010000 | mov eax, dword ptr [esi + 0x3458] // 0f8cee000000 | dec eax // 80fa0d | mov edx, dword ptr [eax] $sequence_9 = { 7514 8a542e10 80fa5c 0f94c1 } // n = 4, score = 200 // 7514 | dec eax // 8a542e10 | mov eax, ebx // 80fa5c | je 0x272 // 0f94c1 | dec eax condition: 7 of them and filesize < 688128 }
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