Avast found this unidentified RAT, which abuses a code-signing certificate by the Philippine Navy. It is statically linked against OpenSSL 1.1.1g.
rule win_unidentified_091_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.unidentified_091." 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_091" malpedia_rule_date = "20230124" malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686" malpedia_version = "20230125" 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 = { eb18 48c745e7ffffffff 0f57c0 0f1145ef 48634104 488b4c1848 4885c9 } // n = 7, score = 100 // eb18 | dec ecx // 48c745e7ffffffff | imul eax, ebx // 0f57c0 | dec esp // 0f1145ef | add ecx, eax // 48634104 | dec eax // 488b4c1848 | mov eax, ebx // 4885c9 | dec eax $sequence_1 = { ff15???????? 448a7709 448a4c2432 83f8ff 7405 884709 eb07 } // n = 7, score = 100 // ff15???????? | // 448a7709 | dec eax // 448a4c2432 | lea eax, [0xec2cd] // 83f8ff | dec eax // 7405 | lea edx, [esp + 0x20] // 884709 | dec eax // eb07 | mov dword ptr [esp + 0x20], eax $sequence_2 = { 4c8d0d289d1000 c7442420fc000000 ba83000000 8d480b 448d4077 e8???????? 4c8bc3 } // n = 7, score = 100 // 4c8d0d289d1000 | inc ecx // c7442420fc000000 | not ecx // ba83000000 | inc ecx // 8d480b | add eax, edi // 448d4077 | add ecx, eax // e8???????? | // 4c8bc3 | inc ecx $sequence_3 = { e8???????? 85c0 0f8522020000 eb19 488d0d2e062700 e8???????? 85c0 } // n = 7, score = 100 // e8???????? | // 85c0 | mov dword ptr [esi + 0x48], edi // 0f8522020000 | dec eax // eb19 | mov dword ptr [esi + 0x50], ebp // 488d0d2e062700 | mov dl, 0x20 // e8???????? | // 85c0 | dec eax $sequence_4 = { ff5250 85c0 7522 41b8a0020000 488d153f7f1100 488bcb e8???????? } // n = 7, score = 100 // ff5250 | mov edx, dword ptr [esp + 0x38] // 85c0 | inc esi // 7522 | mov ecx, dword ptr [edx + ebx + 0x257bb0] // 41b8a0020000 | inc edi // 488d153f7f1100 | xor ecx, dword ptr [eax + ebx + 0x257fb0] // 488bcb | inc edi // e8???????? | $sequence_5 = { e8???????? 8bc7 eb05 b857000780 488b4c2448 4833cc e8???????? } // n = 7, score = 100 // e8???????? | // 8bc7 | mov dword ptr [esp + eax*8 + 0x60], ecx // eb05 | dec eax // b857000780 | inc eax // 488b4c2448 | dec ecx // 4833cc | cmp eax, ecx // e8???????? | $sequence_6 = { c6470801 663b4503 755d c6062d 48ffc6 488b0f 4885c9 } // n = 7, score = 100 // c6470801 | mov ecx, ebx // 663b4503 | jmp 0x168b // 755d | dec eax // c6062d | test eax, eax // 48ffc6 | jne 0x16e9 // 488b0f | inc esp // 4885c9 | lea eax, [eax + 0x62] $sequence_7 = { e8???????? 85c0 7e56 8b07 33f6 33db 85c0 } // n = 7, score = 100 // e8???????? | // 85c0 | je 0x16f7 // 7e56 | mov eax, dword ptr [edi] // 8b07 | sub eax, 0xd800 // 33f6 | cmp eax, 0x3ff // 33db | dec eax // 85c0 | mov dword ptr [esp + 0x20], edi $sequence_8 = { 4889442458 4885c0 7512 c7442420a9010000 e9???????? 488b442458 4c8bcd } // n = 7, score = 100 // 4889442458 | mov dword ptr [esp + 0x28], ecx // 4885c0 | mov dword ptr [esp + 0x20], eax // 7512 | dec ebp // c7442420a9010000 | mov ecx, ebp // e9???????? | // 488b442458 | nop // 4c8bcd | mov eax, dword ptr [edi + esi*4 - 4] $sequence_9 = { 4c8b742440 4c8b6c2448 488b7c2450 488b742458 4883c460 415c 5d } // n = 7, score = 100 // 4c8b742440 | dec eax // 4c8b6c2448 | sub esp, eax // 488b7c2450 | xor ebx, ebx // 488b742458 | inc eax // 4883c460 | push ebx // 415c | push ebp // 5d | inc ecx condition: 7 of them and filesize < 5777408 }
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