According to Seqrite, VELETRIX as been observed as a loader for VShell.
rule win_veletrix_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.veletrix." 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.veletrix" 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 = { 7408 488bc2 e9???????? 4d3bc4 0f84d9000000 8b7500 498b9cf6c0920100 } // n = 7, score = 100 // 7408 | dec eax // 488bc2 | mov edx, ebp // e9???????? | // 4d3bc4 | dec eax // 0f84d9000000 | mov esi, ebp // 8b7500 | dec eax // 498b9cf6c0920100 | add edx, edx $sequence_1 = { f20f59ee f20f5ce9 f2410f1004c1 488d1576860000 f20f1014c2 } // n = 5, score = 100 // f20f59ee | lea edx, [0x902d] // f20f5ce9 | dec eax // f2410f1004c1 | mov ebx, edx // 488d1576860000 | dec esp // f20f1014c2 | lea ecx, [0xaf7c] $sequence_2 = { 85c0 742a 488bc5 4c8d05f5250100 488bcd 48c1f906 83e03f } // n = 7, score = 100 // 85c0 | cmp ebx, edi // 742a | je 0x215 // 488bc5 | je 0x253 // 4c8d05f5250100 | dec eax // 488bcd | mov dword ptr [eax + 8], 0x2ba000 // 48c1f906 | xor ebx, ebx // 83e03f | xor edx, edx $sequence_3 = { e8???????? 33db 8bf8 85c0 0f8453020000 4c8d2d461a0100 448bf3 } // n = 7, score = 100 // e8???????? | // 33db | inc ecx // 8bf8 | mov esi, 4 // 85c0 | dec esp // 0f8453020000 | lea ebx, [eax + eax*2] // 4c8d2d461a0100 | inc ecx // 448bf3 | mov eax, 6 $sequence_4 = { 4c8d0d057c0000 c5f359c1 c5fb101d???????? c5fb102d???????? c4e2f1a91d???????? c4e2f1a92d???????? f20f10e0 } // n = 7, score = 100 // 4c8d0d057c0000 | dec eax // c5f359c1 | imul eax, eax, 1 // c5fb101d???????? | // c5fb102d???????? | // c4e2f1a91d???????? | // c4e2f1a92d???????? | // f20f10e0 | dec eax $sequence_5 = { c7459856697274 488bcb c7459c75616c50 4c8be0 c745a0726f7465 } // n = 5, score = 100 // c7459856697274 | dec eax // 488bcb | mov eax, dword ptr [ecx + 0xf8] // c7459c75616c50 | dec eax // 4c8be0 | mov ebx, ecx // c745a0726f7465 | dec eax $sequence_6 = { e8???????? 488b8f90000000 483b0d???????? 7417 488d05243d0100 } // n = 5, score = 100 // e8???????? | // 488b8f90000000 | test eax, eax // 483b0d???????? | // 7417 | dec eax // 488d05243d0100 | mov ecx, eax $sequence_7 = { 4c8d4c2448 488b4f10 41b840000000 ff542430 8b4f04 ba00080000 } // n = 6, score = 100 // 4c8d4c2448 | mov ecx, dword ptr [ecx + edi*8 + 0x28] // 488b4f10 | inc edx // 41b840000000 | mov byte ptr [ecx + esi*8 + 0x3e], al // ff542430 | dec ebx // 8b4f04 | mov eax, dword ptr [eax + 0x19700] // ba00080000 | inc edx $sequence_8 = { 48894df7 488945ef 488d0d8668ffff 83e03f 458be9 4d03e8 4c8945df } // n = 7, score = 100 // 48894df7 | dec eax // 488945ef | lea edx, [0x8fc6] // 488d0d8668ffff | mov ecx, ebx // 83e03f | dec eax // 458be9 | test eax, eax // 4d03e8 | je 0x3a // 4c8945df | dec esp $sequence_9 = { 4c896daf 49c1fc06 4c8d34c0 4a8b84e100970100 4a8b44f028 } // n = 5, score = 100 // 4c896daf | inc ecx // 49c1fc06 | mov eax, dword ptr [edi + esi*8 + 0x11288] // 4c8d34c0 | test eax, eax // 4a8b84e100970100 | js 0x421 // 4a8b44f028 | cmp eax, 0xe4 condition: 7 of them and filesize < 234496 }
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