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 = "2020-05-30" version = "1" description = "autogenerated rule brought to you by yara-signator" tool = "yara-signator v0.4.0" tool_config = "callsandjumps;datarefs;binvalue" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.cobra" malpedia_rule_date = "20200529" malpedia_hash = "92c362319514e5a6da26204961446caa3a8b32a8" malpedia_version = "20200529" malpedia_license = "CC BY-NC-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 / approach 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 = { 33d2 b9e8030000 f7f1 83f805 } // n = 4, score = 2300 // 33d2 | xor edx, edx // b9e8030000 | mov ecx, 0x3e8 // f7f1 | div ecx // 83f805 | cmp eax, 5 $sequence_2 = { e8???????? 85c0 750e 33ff } // n = 4, score = 2100 // e8???????? | // 85c0 | test eax, eax // 750e | jne 0x10 // 33ff | xor edi, edi $sequence_3 = { ff25???????? 8b442408 85c0 750e 3905???????? 7e2c } // n = 6, score = 2100 // ff25???????? | // 8b442408 | mov eax, dword ptr [esp + 8] // 85c0 | test eax, eax // 750e | jne 0x10 // 3905???????? | // 7e2c | jle 0x2e $sequence_4 = { 5e 5b c3 85db 7405 83fb03 753b } // n = 7, score = 2100 // 5e | pop esi // 5b | pop ebx // c3 | ret // 85db | test ebx, ebx // 7405 | je 7 // 83fb03 | cmp ebx, 3 // 753b | jne 0x3d $sequence_5 = { 757f 8b05???????? 85c0 0f8e8c000000 } // n = 4, score = 2100 // 757f | jne 0x81 // 8b05???????? | // 85c0 | test eax, eax // 0f8e8c000000 | jle 0x92 $sequence_6 = { 5f 5e 5b c3 85ff 7418 } // n = 6, score = 2100 // 5f | pop edi // 5e | pop esi // 5b | pop ebx // c3 | ret // 85ff | test edi, edi // 7418 | je 0x1a $sequence_7 = { e8???????? 8bf8 83fb01 751d 85ff 755d } // n = 6, score = 2100 // e8???????? | // 8bf8 | mov edi, eax // 83fb01 | cmp ebx, 1 // 751d | jne 0x1f // 85ff | test edi, edi // 755d | jne 0x5f $sequence_8 = { 753c b980000000 e8???????? 85c0 a3???????? 7504 33c0 } // n = 7, score = 2100 // 753c | jne 0x3e // b980000000 | mov ecx, 0x80 // e8???????? | // 85c0 | test eax, eax // a3???????? | // 7504 | jne 6 // 33c0 | xor eax, eax $sequence_9 = { 751c 8bcf ff15???????? 8d8fe8030000 } // n = 4, score = 2100 // 751c | jne 0x1e // 8bcf | mov ecx, edi // ff15???????? | // 8d8fe8030000 | lea ecx, [edi + 0x3e8] $sequence_10 = { 5e 5b c3 83fb01 7405 83fb02 } // n = 6, score = 2100 // 5e | pop esi // 5b | pop ebx // c3 | ret // 83fb01 | cmp ebx, 1 // 7405 | je 7 // 83fb02 | cmp ebx, 2 $sequence_11 = { ff25???????? 53 56 57 8bd9 33f6 } // n = 6, score = 2100 // ff25???????? | // 53 | push ebx // 56 | push esi // 57 | push edi // 8bd9 | mov ebx, ecx // 33f6 | xor esi, esi $sequence_12 = { 85c0 0f8e8c000000 83e801 8905???????? } // n = 4, score = 2100 // 85c0 | test eax, eax // 0f8e8c000000 | jle 0x92 // 83e801 | sub eax, 1 // 8905???????? | $sequence_13 = { 740c 80fb64 7507 33c0 e9???????? } // n = 5, score = 1900 // 740c | je 0xe // 80fb64 | cmp bl, 0x64 // 7507 | jne 9 // 33c0 | xor eax, eax // e9???????? | $sequence_14 = { 3c22 7404 3c27 7505 } // n = 4, score = 1700 // 3c22 | cmp al, 0x22 // 7404 | je 6 // 3c27 | cmp al, 0x27 // 7505 | jne 7 $sequence_15 = { ff15???????? 83f87a 7407 3d230000c0 } // n = 4, score = 1600 // ff15???????? | // 83f87a | cmp eax, 0x7a // 7407 | je 9 // 3d230000c0 | cmp eax, 0xc0000023 $sequence_16 = { 53 ff15???????? ff756c 8b35???????? } // n = 4, score = 1500 // 53 | test eax, eax // ff15???????? | // ff756c | mov ecx, dword ptr [ecx] // 8b35???????? | $sequence_17 = { 68???????? 51 ffd6 83c40c 6a28 } // n = 5, score = 800 // 68???????? | // 51 | push ecx // ffd6 | call esi // 83c40c | add esp, 0xc // 6a28 | push 0x28 $sequence_18 = { ff15???????? 83f87a 740b 3d230000c0 } // n = 4, score = 800 // ff15???????? | // 83f87a | cmp eax, 0x7a // 740b | je 0xd // 3d230000c0 | cmp eax, 0xc0000023 $sequence_19 = { 68000000c0 50 ff15???????? 8bf0 83feff 7505 33c0 } // n = 7, score = 800 // 68000000c0 | push 0xc0000000 // 50 | push eax // ff15???????? | // 8bf0 | mov esi, eax // 83feff | cmp esi, -1 // 7505 | jne 7 // 33c0 | xor eax, eax $sequence_20 = { 663bcb 75f4 8b0d???????? 8b15???????? 8908 8b0d???????? 895004 } // n = 7, score = 800 // 663bcb | cmp cx, bx // 75f4 | jne 0xfffffff6 // 8b0d???????? | // 8b15???????? | // 8908 | mov dword ptr [eax], ecx // 8b0d???????? | // 895004 | mov dword ptr [eax + 4], edx $sequence_21 = { ff15???????? eb03 8b7d0c 3bfb } // n = 4, score = 800 // ff15???????? | // eb03 | jmp 5 // 8b7d0c | mov edi, dword ptr [ebp + 0xc] // 3bfb | cmp edi, ebx $sequence_22 = { 83c0fe 668b4802 83c002 663bcb 75f4 8b15???????? } // n = 6, score = 800 // 83c0fe | add eax, -2 // 668b4802 | mov cx, word ptr [eax + 2] // 83c002 | add eax, 2 // 663bcb | cmp cx, bx // 75f4 | jne 0xfffffff6 // 8b15???????? | $sequence_23 = { c3 8b4d08 57 51 6a00 6a00 56 } // n = 7, score = 800 // c3 | ret // 8b4d08 | mov ecx, dword ptr [ebp + 8] // 57 | push edi // 51 | push ecx // 6a00 | push 0 // 6a00 | push 0 // 56 | push esi $sequence_24 = { 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_25 = { 75f4 8b15???????? 8b0d???????? 8910 8b15???????? 894804 } // n = 6, score = 800 // 75f4 | jne 0xfffffff6 // 8b15???????? | // 8b0d???????? | // 8910 | mov dword ptr [eax], edx // 8b15???????? | // 894804 | mov dword ptr [eax + 4], ecx $sequence_26 = { c3 4585e4 75e8 85f6 74e4 418936 b801000000 } // n = 7, score = 700 // c3 | dec ecx // 4585e4 | mov ecx, esp // 75e8 | dec eax // 85f6 | mov dword ptr [edi - 2], eax // 74e4 | jne 0xffffffec // 418936 | xor eax, eax // b801000000 | dec eax $sequence_27 = { 418bf4 4532ff e8???????? 33d2 488d8d300a0000 } // n = 5, score = 700 // 418bf4 | inc ecx // 4532ff | mov esi, esp // e8???????? | // 33d2 | inc ebp // 488d8d300a0000 | xor bh, bh $sequence_28 = { 488b05???????? 498bcc 488947fe 8b05???????? } // n = 4, score = 700 // 488b05???????? | // 498bcc | xor edx, edx // 488947fe | dec eax // 8b05???????? | $sequence_29 = { 75ea 33c0 4883c9ff 488d7da0 66f2af } // n = 5, score = 700 // 75ea | mov ecx, eax // 33c0 | dec eax // 4883c9ff | mov ecx, edi // 488d7da0 | inc ecx // 66f2af | mov bh, 1 $sequence_30 = { 66f2af 48f7d1 66837c4bfc5c 7413 } // n = 4, score = 700 // 66f2af | xor edx, edx // 48f7d1 | dec eax // 66837c4bfc5c | lea ecx, [ebp + 0xa30] // 7413 | repne scasd eax, dword ptr es:[edi] $sequence_31 = { 33d2 488bc8 ff15???????? 488bcf ff15???????? 41b701 e9???????? } // n = 7, score = 700 // 33d2 | dec eax // 488bc8 | not ecx // ff15???????? | // 488bcf | cmp word ptr [ebx + ecx*2 - 4], 0x5c // ff15???????? | // 41b701 | je 0x1e // e9???????? | condition: 7 of them and filesize < 1368064 }
rule win_cobra_w0 { meta: 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_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" 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: 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_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" 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" }
If your designated proposal does not fit in any other category, feel free to write a free-text in the comment field below.
Please propose all changes regarding references on the Malpedia library page
Your suggestion will be reviewed before being published. Thank you for contributing!
YYYY-MM-DD
YYYY-MM
YYYY