Actor(s): Lazarus Group
There is no description at this point.
rule win_badcall_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-03-28" version = "1" description = "Detects win.badcall." 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.badcall" malpedia_rule_date = "20230328" malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d" malpedia_version = "20230407" 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 = { a3???????? a1???????? 50 c705????????04000000 } // n = 4, score = 300 // a3???????? | // a1???????? | // 50 | push eax // c705????????04000000 | $sequence_1 = { c705????????01000000 a1???????? 68???????? 50 } // n = 4, score = 300 // c705????????01000000 | // a1???????? | // 68???????? | // 50 | push eax $sequence_2 = { 50 c705????????04000000 ff15???????? c20400 a1???????? } // n = 5, score = 300 // 50 | push eax // c705????????04000000 | // ff15???????? | // c20400 | ret 4 // a1???????? | $sequence_3 = { 8b442404 48 7455 48 } // n = 4, score = 300 // 8b442404 | mov eax, dword ptr [esp + 4] // 48 | dec eax // 7455 | je 0x57 // 48 | dec eax $sequence_4 = { 0bc8 6a16 6a00 890e 57 56 8bcb } // n = 7, score = 300 // 0bc8 | or ecx, eax // 6a16 | push 0x16 // 6a00 | push 0 // 890e | mov dword ptr [esi], ecx // 57 | push edi // 56 | push esi // 8bcb | mov ecx, ebx $sequence_5 = { e8???????? 83c408 8bce 6a17 6a01 } // n = 5, score = 300 // e8???????? | // 83c408 | add esp, 8 // 8bce | mov ecx, esi // 6a17 | push 0x17 // 6a01 | push 1 $sequence_6 = { 6a17 6a01 57 53 } // n = 4, score = 300 // 6a17 | push 0x17 // 6a01 | push 1 // 57 | push edi // 53 | push ebx $sequence_7 = { 7557 33c0 68???????? a3???????? a3???????? a3???????? a1???????? } // n = 7, score = 300 // 7557 | jne 0x59 // 33c0 | xor eax, eax // 68???????? | // a3???????? | // a3???????? | // a3???????? | // a1???????? | $sequence_8 = { ff15???????? c20400 c705????????01000000 a1???????? } // n = 4, score = 300 // ff15???????? | // c20400 | ret 4 // c705????????01000000 | // a1???????? | $sequence_9 = { 6a00 50 68???????? 6a00 6a00 ffd6 6aff } // n = 7, score = 300 // 6a00 | push 0 // 50 | push eax // 68???????? | // 6a00 | push 0 // 6a00 | push 0 // ffd6 | call esi // 6aff | push -1 $sequence_10 = { 51 6a01 8d542420 53 52 50 ff15???????? } // n = 7, score = 300 // 51 | push ecx // 6a01 | push 1 // 8d542420 | lea edx, [esp + 0x20] // 53 | push ebx // 52 | push edx // 50 | push eax // ff15???????? | $sequence_11 = { c744241810000000 e8???????? 50 ff15???????? 8bf0 83feff } // n = 6, score = 300 // c744241810000000 | mov dword ptr [esp + 0x18], 0x10 // e8???????? | // 50 | push eax // ff15???????? | // 8bf0 | mov esi, eax // 83feff | cmp esi, -1 $sequence_12 = { 7455 48 7434 83e803 } // n = 4, score = 300 // 7455 | je 0x57 // 48 | dec eax // 7434 | je 0x36 // 83e803 | sub eax, 3 $sequence_13 = { 83feff 7450 6a14 6a40 ffd3 8930 } // n = 6, score = 300 // 83feff | cmp esi, -1 // 7450 | je 0x52 // 6a14 | push 0x14 // 6a40 | push 0x40 // ffd3 | call ebx // 8930 | mov dword ptr [eax], esi $sequence_14 = { 7434 83e803 7557 33c0 } // n = 4, score = 300 // 7434 | je 0x36 // 83e803 | sub eax, 3 // 7557 | jne 0x59 // 33c0 | xor eax, eax $sequence_15 = { 7415 8b542408 8b0e 8d44240c 52 50 } // n = 6, score = 300 // 7415 | je 0x17 // 8b542408 | mov edx, dword ptr [esp + 8] // 8b0e | mov ecx, dword ptr [esi] // 8d44240c | lea eax, [esp + 0xc] // 52 | push edx // 50 | push eax condition: 7 of them and filesize < 483328 }
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