Actor(s): Turla Group
There is no description at this point.
rule win_cobra_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2022-08-05" version = "1" description = "Detects win.cobra." 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.cobra" malpedia_rule_date = "20220805" malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71" malpedia_version = "20220808" 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 = { 7511 e8???????? 85c0 7508 ff15???????? } // n = 5, score = 2900 // 7511 | xor eax, eax // e8???????? | // 85c0 | pop ebp // 7508 | ret // ff15???????? | $sequence_1 = { 890d???????? 753c b980000000 e8???????? 85c0 a3???????? 7504 } // n = 7, score = 2500 // 890d???????? | // 753c | jne 0x3e // b980000000 | mov ecx, 0x80 // e8???????? | // 85c0 | test eax, eax // a3???????? | // 7504 | jne 6 $sequence_2 = { 5b c3 83fb01 7405 83fb02 7537 } // n = 6, score = 2500 // 5b | pop ebx // c3 | ret // 83fb01 | cmp ebx, 1 // 7405 | je 7 // 83fb02 | cmp ebx, 2 // 7537 | jne 0x39 $sequence_3 = { 85c0 750e 3905???????? 7e2c ff0d???????? 83f801 } // n = 6, score = 2500 // 85c0 | test eax, eax // 750e | jne 0x10 // 3905???????? | // 7e2c | jle 0x2e // ff0d???????? | // 83f801 | cmp eax, 1 $sequence_4 = { 8b442438 85c0 757f 8b05???????? } // n = 4, score = 2500 // 8b442438 | mov eax, dword ptr [esp + 0x38] // 85c0 | test eax, eax // 757f | jne 0x81 // 8b05???????? | $sequence_5 = { ff25???????? 53 56 57 8bd9 33f6 53 } // n = 7, score = 2500 // ff25???????? | // 53 | push ebx // 56 | push esi // 57 | push edi // 8bd9 | mov ebx, ecx // 33f6 | xor esi, esi // 53 | push ebx $sequence_6 = { 5f 5e 5b c3 85ff 7418 } // n = 6, score = 2500 // 5f | pop edi // 5e | pop esi // 5b | pop ebx // c3 | ret // 85ff | test edi, edi // 7418 | je 0x1a $sequence_7 = { 5b c3 85db 7405 83fb03 753b } // n = 6, score = 2500 // 5b | pop ebx // c3 | ret // 85db | test ebx, ebx // 7405 | je 7 // 83fb03 | cmp ebx, 3 // 753b | jne 0x3d $sequence_8 = { 751c 8bcf ff15???????? 8d8fe8030000 8bf9 } // n = 5, score = 2500 // 751c | jne 0x1e // 8bcf | mov ecx, edi // ff15???????? | // 8d8fe8030000 | lea ecx, [edi + 0x3e8] // 8bf9 | mov edi, ecx $sequence_9 = { 757f 8b05???????? 85c0 0f8e8c000000 83e801 } // n = 5, score = 2500 // 757f | jne 0x81 // 8b05???????? | // 85c0 | test eax, eax // 0f8e8c000000 | jle 0x92 // 83e801 | sub eax, 1 $sequence_10 = { 83f801 75f1 b900010000 e8???????? } // n = 4, score = 2500 // 83f801 | cmp eax, 1 // 75f1 | jne 0xfffffff3 // b900010000 | mov ecx, 0x100 // e8???????? | $sequence_11 = { 7514 391d???????? 754d 33c0 } // n = 4, score = 2500 // 7514 | jne 0x16 // 391d???????? | // 754d | jne 0x4f // 33c0 | xor eax, eax $sequence_12 = { 85c0 a3???????? 7504 33c0 eb68 832000 } // n = 6, score = 2500 // 85c0 | test eax, eax // a3???????? | // 7504 | jne 6 // 33c0 | xor eax, eax // eb68 | jmp 0x6a // 832000 | and dword ptr [eax], 0 $sequence_13 = { 33d2 b9e8030000 f7f1 83f805 } // n = 4, score = 2300 // 33d2 | jmp 0x6c // b9e8030000 | and dword ptr [eax], 0 // f7f1 | mov ecx, dword ptr [ecx] // 83f805 | jne 0x3e $sequence_14 = { ff15???????? 57 89462c ff15???????? } // n = 4, score = 1900 // ff15???????? | // 57 | push edi // 89462c | mov dword ptr [esi + 0x2c], eax // ff15???????? | $sequence_15 = { ff5628 59 59 57 ffd3 } // n = 5, score = 1900 // ff5628 | ret 0xc // 59 | push ebx // 59 | push esi // 57 | push edi // ffd3 | mov ebx, ecx $sequence_16 = { 83f8ff 7407 33c0 e9???????? ff15???????? e9???????? } // n = 6, score = 1900 // 83f8ff | cmp eax, -1 // 7407 | je 9 // 33c0 | xor eax, eax // e9???????? | // ff15???????? | // e9???????? | $sequence_17 = { e8???????? 33db 3bc3 741a } // n = 4, score = 1200 // e8???????? | // 33db | xor ebx, ebx // 3bc3 | cmp eax, ebx // 741a | je 0x1c $sequence_18 = { eb6d e8???????? 85c0 7564 } // n = 4, score = 1200 // eb6d | jmp 0x6f // e8???????? | // 85c0 | test eax, eax // 7564 | jne 0x66 $sequence_19 = { 7f07 e8???????? eb26 83c0ff } // n = 4, score = 1200 // 7f07 | jg 9 // e8???????? | // eb26 | jmp 0x28 // 83c0ff | add eax, -1 $sequence_20 = { b801005921 488b5c2430 488b6c2438 488b742440 488b7c2448 } // n = 5, score = 1100 // b801005921 | mov eax, 0x21590001 // 488b5c2430 | dec eax // 488b6c2438 | mov ebx, dword ptr [esp + 0x30] // 488b742440 | dec eax // 488b7c2448 | mov ebp, dword ptr [esp + 0x38] $sequence_21 = { 83385c 7e4b 4c8b505c 4d85d2 7442 448b6c2470 4c8bce } // n = 7, score = 1100 // 83385c | jne 0x66 // 7e4b | dec eax // 4c8b505c | mov ecx, dword ptr [ebx] // 4d85d2 | test eax, eax // 7442 | mov esi, eax // 448b6c2470 | jne 0x2c // 4c8bce | dec eax $sequence_22 = { 85c0 8bf0 7521 48833f00 } // n = 4, score = 1100 // 85c0 | dec eax // 8bf0 | mov eax, dword ptr [ecx] // 7521 | jmp 0x6f // 48833f00 | test eax, eax $sequence_23 = { 83781400 750a b865005921 e9???????? } // n = 4, score = 900 // 83781400 | cmp dword ptr [eax + 0x14], 0 // 750a | jne 0xc // b865005921 | mov eax, 0x21590065 // e9???????? | $sequence_24 = { 663bcb 75f4 8b15???????? 8b0d???????? } // n = 4, score = 800 // 663bcb | ret // 75f4 | test ebx, ebx // 8b15???????? | // 8b0d???????? | $sequence_25 = { 51 6a00 6a00 56 ff15???????? 56 } // n = 6, score = 800 // 51 | je 0xb // 6a00 | pop edi // 6a00 | pop esi // 56 | pop ebx // ff15???????? | // 56 | ret $sequence_26 = { 68000000c0 50 ff15???????? 8bf0 83feff 7505 } // n = 6, score = 800 // 68000000c0 | mov dword ptr [eax], edx // 50 | push ebx // ff15???????? | // 8bf0 | push esi // 83feff | xor ebx, ebx // 7505 | push edi $sequence_27 = { 663bcb 75f4 8b0d???????? 8b15???????? 8908 8b0d???????? } // n = 6, score = 800 // 663bcb | ret // 75f4 | cmp ebx, 1 // 8b0d???????? | // 8b15???????? | // 8908 | je 0xd // 8b0d???????? | $sequence_28 = { 5e 5d c3 8b4d08 57 51 6a00 } // n = 7, score = 800 // 5e | test eax, eax // 5d | jne 0x10 // c3 | xor edi, edi // 8b4d08 | mov eax, edi // 57 | push ecx // 51 | call esi // 6a00 | add esp, 0xc $sequence_29 = { 8d45e8 50 6a00 6aff e8???????? 85c0 7405 } // n = 7, score = 800 // 8d45e8 | lea eax, [ebp - 0x18] // 50 | push eax // 6a00 | push 0 // 6aff | push -1 // e8???????? | // 85c0 | test eax, eax // 7405 | je 7 $sequence_30 = { 6689440ffc 6685c0 75ee f685c003000010 } // n = 4, score = 800 // 6689440ffc | cmp ebx, 2 // 6685c0 | pop esi // 75ee | pop ebx // f685c003000010 | ret $sequence_31 = { 53 56 33db 57 6808020000 } // n = 5, score = 800 // 53 | push 0xc0000000 // 56 | mov dword ptr [eax + 4], edx // 33db | mov dword ptr [eax + 8], ecx // 57 | xor eax, eax // 6808020000 | cmp cx, bx $sequence_32 = { 8908 8b0d???????? 895004 894808 33c0 } // n = 5, score = 800 // 8908 | push 0x28 // 8b0d???????? | // 895004 | cmp cx, bx // 894808 | jne 0xfffffff6 // 33c0 | push ecx $sequence_33 = { 68???????? 51 ffd6 83c40c 6a28 } // n = 5, score = 800 // 68???????? | // 51 | xor eax, eax // ffd6 | pop edi // 83c40c | pop esi // 6a28 | pop ebx $sequence_34 = { ff15???????? 83f87a 740b 3d230000c0 } // n = 4, score = 800 // ff15???????? | // 83f87a | ret // 740b | cmp ebx, 1 // 3d230000c0 | je 0xb $sequence_35 = { 48894c2450 4c89642448 488d4c2468 48894c2440 4c89642438 } // n = 5, score = 700 // 48894c2450 | je 0x1c // 4c89642448 | pop ebx // 488d4c2468 | ret // 48894c2440 | test ebx, ebx // 4c89642438 | je 9 $sequence_36 = { ff15???????? 488bcf ff15???????? 41b701 } // n = 4, score = 700 // ff15???????? | // 488bcf | test al, al // ff15???????? | // 41b701 | cmovne edi, ecx $sequence_37 = { 5b 5d c3 4585e4 } // n = 4, score = 700 // 5b | mov dword ptr [esp + 0x48], esp // 5d | dec eax // c3 | lea ecx, [esp + 0x68] // 4585e4 | dec eax $sequence_38 = { 498bcd ff15???????? 4c8bac24400d0000 488bbc24880d0000 4885db } // n = 5, score = 700 // 498bcd | mov ecx, esi // ff15???????? | // 4c8bac24400d0000 | mov edx, edi // 488bbc24880d0000 | test eax, eax // 4885db | dec esp $sequence_39 = { b914000000 84c0 0f45f9 488bce 8bd7 } // n = 5, score = 700 // b914000000 | cmp ebx, 1 // 84c0 | je 0xc // 0f45f9 | pop ebx // 488bce | ret // 8bd7 | test edi, edi $sequence_40 = { 8d8588feffff 68???????? 50 ff15???????? 83c42c } // n = 5, score = 700 // 8d8588feffff | jne 0x3e // 68???????? | // 50 | mov ecx, 0x80 // ff15???????? | // 83c42c | test eax, eax $sequence_41 = { 488bce 8bd7 ff15???????? 85c0 } // n = 4, score = 700 // 488bce | dec eax // 8bd7 | lea ecx, [esp + 0x68] // ff15???????? | // 85c0 | dec eax $sequence_42 = { 7507 32c0 e9???????? c745b818000000 } // n = 4, score = 600 // 7507 | jne 9 // 32c0 | xor al, al // e9???????? | // c745b818000000 | mov dword ptr [ebp - 0x48], 0x18 $sequence_43 = { 668b08 83c002 6685c9 75f5 2bc2 d1f8 66837c43fe5c } // n = 7, score = 500 // 668b08 | mov eax, dword ptr [esp + 8] // 83c002 | test eax, eax // 6685c9 | jne 0x10 // 75f5 | jle 0x30 // 2bc2 | jne 0x3e // d1f8 | mov ecx, 0x80 // 66837c43fe5c | test eax, eax $sequence_44 = { 0f8456feffff 807c241301 6800080000 0f8544020000 } // n = 4, score = 300 // 0f8456feffff | push eax // 807c241301 | lea ecx, [esp + 0xd9c] // 6800080000 | push ecx // 0f8544020000 | add eax, 0xa2 $sequence_45 = { 0f8431ffffff 8b4d08 5f 8931 } // n = 4, score = 300 // 0f8431ffffff | add eax, 0xa1 // 8b4d08 | push eax // 5f | lea eax, [esp + 0xd9c] // 8931 | add eax, 0xa1 $sequence_46 = { 05a2000000 50 8d8c249c0d0000 68???????? } // n = 4, score = 300 // 05a2000000 | test eax, eax // 50 | jne 0x10 // 8d8c249c0d0000 | jle 0x30 // 68???????? | $sequence_47 = { 0f84100f0000 6800080000 57 56 } // n = 4, score = 300 // 0f84100f0000 | add esp, 0x2c // 6800080000 | mov cx, word ptr [eax] // 57 | add eax, 2 // 56 | test cx, cx $sequence_48 = { 05a1000000 50 8d84249c0d0000 68???????? } // n = 4, score = 300 // 05a1000000 | jne 0x12 // 50 | jle 0x32 // 8d84249c0d0000 | test eax, eax // 68???????? | $sequence_49 = { 05a2000000 50 8d94249c0d0000 68???????? } // n = 4, score = 300 // 05a2000000 | jne 0xc // 50 | jne 0x13 // 8d94249c0d0000 | test eax, eax // 68???????? | $sequence_50 = { 85c0 740a b8050000c0 e9???????? } // n = 4, score = 200 // 85c0 | test eax, eax // 740a | je 0xc // b8050000c0 | mov eax, 0xc0000005 // e9???????? | $sequence_51 = { 668cc8 c3 53 50 } // n = 4, score = 200 // 668cc8 | mov ax, cs // c3 | ret // 53 | push ebx // 50 | push eax $sequence_52 = { c745b800000000 c745c000000000 c745bc00000000 c745c400000000 c745c800000000 8b5508 } // n = 6, score = 100 // c745b800000000 | mov dword ptr [ebp - 0x48], 0 // c745c000000000 | mov dword ptr [ebp - 0x40], 0 // c745bc00000000 | mov dword ptr [ebp - 0x44], 0 // c745c400000000 | mov dword ptr [ebp - 0x3c], 0 // c745c800000000 | mov dword ptr [ebp - 0x38], 0 // 8b5508 | mov edx, dword ptr [ebp + 8] $sequence_53 = { c745b800000000 c745c000000000 c745c400000000 8b4d08 } // n = 4, score = 100 // c745b800000000 | mov dword ptr [ebp - 0x48], 0 // c745c000000000 | mov dword ptr [ebp - 0x40], 0 // c745c400000000 | mov dword ptr [ebp - 0x3c], 0 // 8b4d08 | mov ecx, dword ptr [ebp + 8] condition: 7 of them and filesize < 1368064 }
rule win_cobra_w0 { meta: author = "ESET Research" source = "https://www.welivesecurity.com/2017/03/30/carbon-paper-peering-turlas-second-stage-backdoor/#_footnote_2" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.cobra" malpedia_version = "20170512" malpedia_sharing = "TLP:WHITE" malpedia_license = "" strings: $s1 = "ModStart" $s2 = "ModuleStart" $t1 = "STOP|OK" $t2 = "STOP|KILL" condition: (uint16(0) == 0x5a4d) and (1 of ($s*)) and (1 of ($t*)) }
import "pe" rule win_cobra_w1 { meta: author = "ESET Research" source = "https://www.welivesecurity.com/2017/03/30/carbon-paper-peering-turlas-second-stage-backdoor/#_footnote_2" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.cobra" malpedia_version = "20170512" malpedia_sharing = "TLP:WHITE" malpedia_license = "" condition: (pe.version_info["InternalName"] contains "SERVICE.EXE" or pe.version_info["InternalName"] contains "MSIMGHLP.DLL" or pe.version_info["InternalName"] contains "MSXIML.DLL") and pe.version_info["CompanyName"] contains "Microsoft Corporation" }
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