Ransomware.
rule win_thunderx_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.thunderx." 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.thunderx" 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 = { c745fc01000000 50 ff15???????? 50 ff15???????? 85c0 741b } // n = 7, score = 200 // c745fc01000000 | mov dword ptr [ebp - 4], 1 // 50 | push eax // ff15???????? | // 50 | push eax // ff15???????? | // 85c0 | test eax, eax // 741b | je 0x1d $sequence_1 = { 8bce e8???????? eb0c 83fb03 7570 8bce } // n = 6, score = 200 // 8bce | mov ecx, esi // e8???????? | // eb0c | jmp 0xe // 83fb03 | cmp ebx, 3 // 7570 | jne 0x72 // 8bce | mov ecx, esi $sequence_2 = { 8d4db0 e8???????? 8bc7 e8???????? c3 55 8bec } // n = 7, score = 200 // 8d4db0 | lea ecx, [ebp - 0x50] // e8???????? | // 8bc7 | mov eax, edi // e8???????? | // c3 | ret // 55 | push ebp // 8bec | mov ebp, esp $sequence_3 = { 33c8 894da8 8b45a0 03c1 6a12 50 } // n = 6, score = 200 // 33c8 | xor ecx, eax // 894da8 | mov dword ptr [ebp - 0x58], ecx // 8b45a0 | mov eax, dword ptr [ebp - 0x60] // 03c1 | add eax, ecx // 6a12 | push 0x12 // 50 | push eax $sequence_4 = { 3145b4 83c440 8b4598 0345b8 } // n = 4, score = 200 // 3145b4 | xor dword ptr [ebp - 0x4c], eax // 83c440 | add esp, 0x40 // 8b4598 | mov eax, dword ptr [ebp - 0x68] // 0345b8 | add eax, dword ptr [ebp - 0x48] $sequence_5 = { ff35???????? ff15???????? 8b75ec 85f6 74d3 85c0 74cf } // n = 7, score = 200 // ff35???????? | // ff15???????? | // 8b75ec | mov esi, dword ptr [ebp - 0x14] // 85f6 | test esi, esi // 74d3 | je 0xffffffd5 // 85c0 | test eax, eax // 74cf | je 0xffffffd1 $sequence_6 = { 85d2 7417 8d45bc 2bf0 } // n = 4, score = 200 // 85d2 | test edx, edx // 7417 | je 0x19 // 8d45bc | lea eax, [ebp - 0x44] // 2bf0 | sub esi, eax $sequence_7 = { 50 ff15???????? 8d8d84fbffff 8985b8fbffff e8???????? 6887690000 } // n = 6, score = 200 // 50 | push eax // ff15???????? | // 8d8d84fbffff | lea ecx, [ebp - 0x47c] // 8985b8fbffff | mov dword ptr [ebp - 0x448], eax // e8???????? | // 6887690000 | push 0x6987 $sequence_8 = { c1f906 6bf638 8b0c8d701b4200 80643128fd 5f } // n = 5, score = 200 // c1f906 | sar ecx, 6 // 6bf638 | imul esi, esi, 0x38 // 8b0c8d701b4200 | mov ecx, dword ptr [ecx*4 + 0x421b70] // 80643128fd | and byte ptr [ecx + esi + 0x28], 0xfd // 5f | pop edi $sequence_9 = { c1fa06 83e03f 6bf838 8955f8 8b1495701b4200 897df4 } // n = 6, score = 200 // c1fa06 | sar edx, 6 // 83e03f | and eax, 0x3f // 6bf838 | imul edi, eax, 0x38 // 8955f8 | mov dword ptr [ebp - 8], edx // 8b1495701b4200 | mov edx, dword ptr [edx*4 + 0x421b70] // 897df4 | mov dword ptr [ebp - 0xc], edi condition: 7 of them and filesize < 319488 }
import "pe" rule win_thunderx_w0 { meta: description = "Rule to dettect tthe ThunderX ransomware family" author = "Christiaan Beek @ McAfee ATR team" date = "2020-09-14" rule_version = "v1" malware_type = "ransomware" malware_family = "Ransomware:W32/ThunderX" actor_type = "Cybercrime" actor_group = "Unknown" hash1 = "7bab5dedef124803668580a59b6bf3c53cc31150d19591567397bbc131b9ccb6" hash2 = "0fbfdb8340108fafaca4c5ff4d3c9f9a2296efeb9ae89fcd9210e3d4c7239666" hash3 = "7527459500109b3bb48665236c5c5cb2ec71ba789867ad2b6417b38b9a46615e" source = "https://github.com/advanced-threat-research/Yara-Rules/blob/master/ransomware/Ransom_ThunderX.yar" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.thunderx" malpedia_rule_date = "20200915" malpedia_hash = "" malpedia_version = "20200915" malpedia_license = "CC BY-SA 4.0" malpedia_sharing = "TLP:WHITE" strings: $pattern1 = "626364656469742E657865202F736574207B64656661756C747D20626F6F74737461747573706F6C6963792069676E6F7265616C6C6661696C75726573" $s3 = "776261646D696E2044454C4554452053595354454D53544154454241434B5550202D64656C6574654F6C64657374" ascii $s4 = "626364656469742E657865202F736574207B64656661756C747D207265636F76657279656E61626C6564204E6F" ascii $s5 = "776261646D696E2044454C4554452053595354454D53544154454241434B5550" ascii $s6 = "433A5C50726F6772616D2046696C65732028783836295C4D6963726F736F66742053514C20536572766572" ascii $s7 = "476C6F62616C5C33353335354641352D303745392D343238422D423541352D314338384341423242343838" ascii $s8 = "433A5C50726F6772616D2046696C65735C4D6963726F736F66742053514C20536572766572" ascii $s9 = "76737361646D696E2E6578652044656C65746520536861646F7773202F416C6C202F5175696574" ascii $s10 = "776D69632E65786520534841444F57434F5059202F6E6F696E746572616374697665" ascii $s11 = "534F4654574152455C4D6963726F736F66745C45524944" ascii $s12 = "AppPolicyGetProcessTerminationMethod" fullword ascii $s13 = "7B5041545445524E5F49447D" ascii $s14 = "726561646D652E747874" ascii $s15 = "226E6574776F726B223A22" ascii $s16 = "227375626964223A22" ascii $s17 = "226C616E67223A22" ascii $s18 = "22657874223A22" ascii $s19 = "69642E6B6579" ascii $s20 = "7B5549447D" ascii $seq0 = { eb 34 66 0f 12 0d 10 c4 41 00 f2 0f 59 c1 ba cc } $seq1 = { 6a 07 50 e8 51 ff ff ff 8d 86 d0 } $seq2 = { ff 15 34 81 41 00 eb 15 83 f8 fc 75 10 8b 45 f4 } condition: ( uint16(0) == 0x5a4d and filesize < 400KB and pe.imphash() == "ea7e408cd2a264fd13492973e97d8d70" and $pattern1 and 4 of them ) and all of ($seq*) or ( all of them ) }
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