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 = "2021-10-07" 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 = "20211007" malpedia_hash = "e5b790e0f888f252d49063a1251ca60ec2832535" malpedia_version = "20211008" 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 | jne 0x13 // e8???????? | // 85c0 | test eax, eax // 7508 | jne 0xa // ff15???????? | $sequence_1 = { c3 83f801 75f1 b900010000 } // n = 4, score = 2500 // c3 | ret // 83f801 | cmp eax, 1 // 75f1 | jne 0xfffffff3 // b900010000 | mov ecx, 0x100 $sequence_2 = { 85c0 0f8e8c000000 83e801 8905???????? } // n = 4, score = 2500 // 85c0 | test eax, eax // 0f8e8c000000 | jle 0x92 // 83e801 | sub eax, 1 // 8905???????? | $sequence_3 = { 5b c3 83fb01 7405 83fb02 } // n = 5, score = 2500 // 5b | pop ebx // c3 | ret // 83fb01 | cmp ebx, 1 // 7405 | je 7 // 83fb02 | cmp ebx, 2 $sequence_4 = { b980000000 e8???????? 85c0 a3???????? } // n = 4, score = 2500 // b980000000 | mov ecx, 0x80 // e8???????? | // 85c0 | test eax, eax // a3???????? | $sequence_5 = { 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_6 = { e8???????? 8bf8 83fb01 751d } // n = 4, score = 2500 // e8???????? | // 8bf8 | mov edi, eax // 83fb01 | cmp ebx, 1 // 751d | jne 0x1f $sequence_7 = { c20c00 ff25???????? 53 56 57 8bd9 33f6 } // n = 7, score = 2500 // c20c00 | ret 0xc // ff25???????? | // 53 | push ebx // 56 | push esi // 57 | push edi // 8bd9 | mov ebx, ecx // 33f6 | xor esi, esi $sequence_8 = { 8b442408 85c0 750e 3905???????? 7e2c ff0d???????? } // n = 6, score = 2500 // 8b442408 | mov eax, dword ptr [esp + 8] // 85c0 | test eax, eax // 750e | jne 0x10 // 3905???????? | // 7e2c | jle 0x2e // ff0d???????? | $sequence_9 = { 83fb01 751d 85ff 755d } // n = 4, score = 2500 // 83fb01 | cmp ebx, 1 // 751d | jne 0x1f // 85ff | test edi, edi // 755d | jne 0x5f $sequence_10 = { 85c0 750e 33ff 8bc7 } // n = 4, score = 2500 // 85c0 | test eax, eax // 750e | jne 0x10 // 33ff | xor edi, edi // 8bc7 | mov eax, edi $sequence_11 = { 5e 5b c3 85ff 7418 } // n = 5, score = 2500 // 5e | pop esi // 5b | pop ebx // c3 | ret // 85ff | test edi, edi // 7418 | je 0x1a $sequence_12 = { 85c0 a3???????? 7504 33c0 eb68 } // n = 5, score = 2500 // 85c0 | test eax, eax // a3???????? | // 7504 | jne 6 // 33c0 | xor eax, eax // eb68 | jmp 0x6a $sequence_13 = { 33d2 b9e8030000 f7f1 83f805 } // n = 4, score = 2300 // 33d2 | xor edx, edx // b9e8030000 | mov ecx, 0x3e8 // f7f1 | div ecx // 83f805 | cmp eax, 5 $sequence_14 = { 899e98130000 c686c813000001 8bc6 eb0c 3bfb 7406 c707feffffff } // n = 7, score = 1900 // 899e98130000 | mov dword ptr [esi + 0x1398], ebx // c686c813000001 | mov byte ptr [esi + 0x13c8], 1 // 8bc6 | mov eax, esi // eb0c | jmp 0xe // 3bfb | cmp edi, ebx // 7406 | je 8 // c707feffffff | mov dword ptr [edi], 0xfffffffe $sequence_15 = { 7425 397e2c 7420 ffd5 8bf8 8d442418 50 } // n = 7, score = 1900 // 7425 | je 0x27 // 397e2c | cmp dword ptr [esi + 0x2c], edi // 7420 | je 0x22 // ffd5 | call ebp // 8bf8 | mov edi, eax // 8d442418 | lea eax, dword ptr [esp + 0x18] // 50 | push eax $sequence_16 = { 740c ff33 ff15???????? 832300 59 8bc6 5e } // n = 7, score = 1900 // 740c | je 0xe // ff33 | push dword ptr [ebx] // ff15???????? | // 832300 | and dword ptr [ebx], 0 // 59 | pop ecx // 8bc6 | mov eax, esi // 5e | pop esi $sequence_17 = { 80fb64 7507 33c0 e9???????? } // n = 4, score = 1900 // 80fb64 | cmp bl, 0x64 // 7507 | jne 9 // 33c0 | xor eax, eax // e9???????? | $sequence_18 = { 7406 83430401 eb04 834b08ff } // n = 4, score = 1200 // 7406 | test eax, eax // 83430401 | jne 0xd // eb04 | test eax, eax // 834b08ff | jne 6 $sequence_19 = { 8d7701 ff15???????? 8b4304 217b08 85c0 } // n = 5, score = 1200 // 8d7701 | mov eax, dword ptr [esp + 8] // ff15???????? | // 8b4304 | test eax, eax // 217b08 | jne 0x12 // 85c0 | jle 0x32 $sequence_20 = { 5d c3 8bc5 ebe4 } // n = 4, score = 1200 // 5d | test eax, eax // c3 | jne 0xc // 8bc5 | jne 0x13 // ebe4 | test eax, eax $sequence_21 = { e8???????? 33db 3bc3 741a } // n = 4, score = 1200 // e8???????? | // 33db | jne 0xc // 3bc3 | xor edx, edx // 741a | mov ecx, 0x3e8 $sequence_22 = { 894c2450 740f 034810 894c2450 } // n = 4, score = 1200 // 894c2450 | test eax, eax // 740f | jne 0x12 // 034810 | jle 0x32 // 894c2450 | cmp eax, 1 $sequence_23 = { 85c0 7f07 e8???????? eb26 } // n = 4, score = 1200 // 85c0 | jne 0x10 // 7f07 | jle 0x30 // e8???????? | // eb26 | jne 0x13 $sequence_24 = { 83781400 750a b865005921 e9???????? } // n = 4, score = 900 // 83781400 | cmp dword ptr [eax + 0x14], 0 // 750a | jne 0xc // b865005921 | mov eax, 0x21590065 // e9???????? | $sequence_25 = { 83feff 7505 33c0 5e 5d c3 8b4d08 } // n = 7, score = 800 // 83feff | cmp esi, -1 // 7505 | jne 7 // 33c0 | xor eax, eax // 5e | pop esi // 5d | pop ebp // c3 | ret // 8b4d08 | mov ecx, dword ptr [ebp + 8] $sequence_26 = { 8bec 56 6a00 6880000000 6a03 6a00 6a03 } // n = 7, score = 800 // 8bec | mov ebp, esp // 56 | push esi // 6a00 | push 0 // 6880000000 | push 0x80 // 6a03 | push 3 // 6a00 | push 0 // 6a03 | push 3 $sequence_27 = { ff15???????? 83f87a 740b 3d230000c0 } // n = 4, score = 800 // ff15???????? | // 83f87a | cmp eax, 0x7a // 740b | je 0xd // 3d230000c0 | cmp eax, 0xc0000023 $sequence_28 = { 53 56 33db 57 6808020000 } // n = 5, score = 800 // 53 | push ebx // 56 | push esi // 33db | xor ebx, ebx // 57 | push edi // 6808020000 | push 0x208 $sequence_29 = { 83c002 663bcb 75f4 8b15???????? 8b0d???????? 8910 } // n = 6, score = 800 // 83c002 | add eax, 2 // 663bcb | cmp cx, bx // 75f4 | jne 0xfffffff6 // 8b15???????? | // 8b0d???????? | // 8910 | mov dword ptr [eax], edx $sequence_30 = { 8b4d08 57 51 6a00 6a00 56 ff15???????? } // n = 7, score = 800 // 8b4d08 | mov ecx, dword ptr [ebp + 8] // 57 | push edi // 51 | push ecx // 6a00 | push 0 // 6a00 | push 0 // 56 | push esi // ff15???????? | $sequence_31 = { 8b7d0c 3bc3 7508 3bfb } // n = 4, score = 800 // 8b7d0c | mov edi, dword ptr [ebp + 0xc] // 3bc3 | cmp eax, ebx // 7508 | jne 0xa // 3bfb | cmp edi, ebx $sequence_32 = { 6689440ffc 6685c0 75ee f685c003000010 } // n = 4, score = 800 // 6689440ffc | mov word ptr [edi + ecx - 4], ax // 6685c0 | test ax, ax // 75ee | jne 0xfffffff0 // f685c003000010 | test byte ptr [ebp + 0x3c0], 0x10 $sequence_33 = { 8908 8b0d???????? 895004 894808 33c0 } // n = 5, score = 800 // 8908 | mov dword ptr [eax], ecx // 8b0d???????? | // 895004 | mov dword ptr [eax + 4], edx // 894808 | mov dword ptr [eax + 8], ecx // 33c0 | xor eax, eax $sequence_34 = { 83c002 663bcb 75f4 8b0d???????? 8b15???????? 8908 8b0d???????? } // n = 7, score = 800 // 83c002 | add eax, 2 // 663bcb | cmp cx, bx // 75f4 | jne 0xfffffff6 // 8b0d???????? | // 8b15???????? | // 8908 | mov dword ptr [eax], ecx // 8b0d???????? | $sequence_35 = { 8d45e8 50 6a00 6aff e8???????? 85c0 } // n = 6, score = 800 // 8d45e8 | lea eax, dword ptr [ebp - 0x18] // 50 | push eax // 6a00 | push 0 // 6aff | push -1 // e8???????? | // 85c0 | test eax, eax $sequence_36 = { 66837c4bfc5c 7413 488bfb 4883c9ff 66f2af } // n = 5, score = 700 // 66837c4bfc5c | mov dword ptr [esi], esi // 7413 | mov eax, 1 // 488bfb | dec eax // 4883c9ff | add esp, 0xd48 // 66f2af | je 0xffffffe6 $sequence_37 = { ffc6 85c0 7509 4885db } // n = 4, score = 700 // ffc6 | pop edi // 85c0 | inc ecx // 7509 | pop esi // 4885db | inc ecx $sequence_38 = { 894706 ff15???????? 4c8be8 4883f8ff } // n = 4, score = 700 // 894706 | pop esi // ff15???????? | // 4c8be8 | pop ebx // 4883f8ff | pop ebp $sequence_39 = { 74e4 418936 b801000000 4881c4480d0000 } // n = 4, score = 700 // 74e4 | ret // 418936 | inc ebp // b801000000 | xor ecx, ecx // 4881c4480d0000 | mov edx, 0xc0000000 $sequence_40 = { 4533c9 ba000000c0 c744242880000000 c744242003000000 ff15???????? 488bf8 4883f8ff } // n = 7, score = 700 // 4533c9 | mov ecx, ebp // ba000000c0 | dec esp // c744242880000000 | mov ebp, dword ptr [esp + 0xd40] // c744242003000000 | inc ecx // ff15???????? | // 488bf8 | pop edi // 4883f8ff | inc ecx $sequence_41 = { ff15???????? 83f812 410f44c4 448be0 498bcd } // n = 5, score = 700 // ff15???????? | // 83f812 | cmp eax, 0x12 // 410f44c4 | inc ecx // 448be0 | cmove eax, esp // 498bcd | inc esp $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 = { 85c0 740a b8050000c0 e9???????? } // n = 4, score = 200 // 85c0 | test eax, eax // 740a | je 0xc // b8050000c0 | mov eax, 0xc0000005 // e9???????? | $sequence_44 = { 668cc8 c3 53 50 } // n = 4, score = 200 // 668cc8 | mov ax, cs // c3 | ret // 53 | push ebx // 50 | push eax $sequence_45 = { c7422402000000 eb2d 8b45f8 0fbe4801 } // n = 4, score = 100 // c7422402000000 | mov dword ptr [edx + 0x24], 2 // eb2d | jmp 0x2f // 8b45f8 | mov eax, dword ptr [ebp - 8] // 0fbe4801 | movsx ecx, byte ptr [eax + 1] $sequence_46 = { c7422403000000 eb0c c78574ffffff66005921 eb3d } // n = 4, score = 100 // c7422403000000 | mov dword ptr [edx + 0x24], 3 // eb0c | jmp 0xe // c78574ffffff66005921 | mov dword ptr [ebp - 0x8c], 0x21590066 // eb3d | jmp 0x3f 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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