Actor(s): Lazarus Group
There is no description at this point.
rule win_bravonc_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-03-28" version = "1" description = "Detects win.bravonc." 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.bravonc" 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 = { 7e62 eb03 8b45f8 2b45f4 3b4628 7f55 8b4d0c } // n = 7, score = 100 // 7e62 | jle 0x64 // eb03 | jmp 5 // 8b45f8 | mov eax, dword ptr [ebp - 8] // 2b45f4 | sub eax, dword ptr [ebp - 0xc] // 3b4628 | cmp eax, dword ptr [esi + 0x28] // 7f55 | jg 0x57 // 8b4d0c | mov ecx, dword ptr [ebp + 0xc] $sequence_1 = { 3b5d0c 7c92 5f 5e } // n = 4, score = 100 // 3b5d0c | cmp ebx, dword ptr [ebp + 0xc] // 7c92 | jl 0xffffff94 // 5f | pop edi // 5e | pop esi $sequence_2 = { 8d8568ffffff 6a14 50 8d857cffffff 50 e8???????? } // n = 6, score = 100 // 8d8568ffffff | lea eax, [ebp - 0x98] // 6a14 | push 0x14 // 50 | push eax // 8d857cffffff | lea eax, [ebp - 0x84] // 50 | push eax // e8???????? | $sequence_3 = { 0bca 8b96c0000000 034a30 034df0 8d9c01dcbc1b8f 895df0 e8???????? } // n = 7, score = 100 // 0bca | or ecx, edx // 8b96c0000000 | mov edx, dword ptr [esi + 0xc0] // 034a30 | add ecx, dword ptr [edx + 0x30] // 034df0 | add ecx, dword ptr [ebp - 0x10] // 8d9c01dcbc1b8f | lea ebx, [ecx + eax - 0x70e44324] // 895df0 | mov dword ptr [ebp - 0x10], ebx // e8???????? | $sequence_4 = { 894634 e9???????? c70609000000 c74718a8e24000 eb91 837df4fd eb4c } // n = 7, score = 100 // 894634 | mov dword ptr [esi + 0x34], eax // e9???????? | // c70609000000 | mov dword ptr [esi], 9 // c74718a8e24000 | mov dword ptr [edi + 0x18], 0x40e2a8 // eb91 | jmp 0xffffff93 // 837df4fd | cmp dword ptr [ebp - 0xc], -3 // eb4c | jmp 0x4e $sequence_5 = { 8d4dcc e8???????? 83c8ff 8b4df4 5f 5e 5b } // n = 7, score = 100 // 8d4dcc | lea ecx, [ebp - 0x34] // e8???????? | // 83c8ff | or eax, 0xffffffff // 8b4df4 | mov ecx, dword ptr [ebp - 0xc] // 5f | pop edi // 5e | pop esi // 5b | pop ebx $sequence_6 = { ff15???????? 59 8bf0 ff15???????? 03f0 ff15???????? 03f0 } // n = 7, score = 100 // ff15???????? | // 59 | pop ecx // 8bf0 | mov esi, eax // ff15???????? | // 03f0 | add esi, eax // ff15???????? | // 03f0 | add esi, eax $sequence_7 = { c7461890e34000 eb1a 83f8fd 7509 } // n = 4, score = 100 // c7461890e34000 | mov dword ptr [esi + 0x18], 0x40e390 // eb1a | jmp 0x1c // 83f8fd | cmp eax, -3 // 7509 | jne 0xb $sequence_8 = { 59 0f8cb8000000 8d450b 6a01 50 8d8d98efffff 885d0b } // n = 7, score = 100 // 59 | pop ecx // 0f8cb8000000 | jl 0xbe // 8d450b | lea eax, [ebp + 0xb] // 6a01 | push 1 // 50 | push eax // 8d8d98efffff | lea ecx, [ebp - 0x1068] // 885d0b | mov byte ptr [ebp + 0xb], bl $sequence_9 = { 5b 8d4de0 53 57 e8???????? } // n = 5, score = 100 // 5b | pop ebx // 8d4de0 | lea ecx, [ebp - 0x20] // 53 | push ebx // 57 | push edi // e8???????? | condition: 7 of them and filesize < 131072 }
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