Actor(s): APT39, Chafer
There is no description at this point.
rule win_remexi_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2020-10-14" version = "1" description = "autogenerated rule brought to you by yara-signator" tool = "yara-signator v0.5.0" tool_config = "callsandjumps;datarefs;binvalue" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.remexi" malpedia_rule_date = "20201014" malpedia_hash = "a7e3bd57eaf12bf3ea29a863c041091ba3af9ac9" malpedia_version = "20201014" 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 = { 56 c706ffffffff e8???????? 83c404 } // n = 4, score = 300 // 56 | push esi // c706ffffffff | mov dword ptr [esi], 0xffffffff // e8???????? | // 83c404 | add esp, 4 $sequence_1 = { 6a00 6a02 c785ccfeffff28010000 ff15???????? } // n = 4, score = 200 // 6a00 | push 0 // 6a02 | push 2 // c785ccfeffff28010000 | mov dword ptr [ebp - 0x134], 0x128 // ff15???????? | $sequence_2 = { 50 a3???????? c705????????02000000 890d???????? ffd6 6a00 } // n = 6, score = 200 // 50 | push eax // a3???????? | // c705????????02000000 | // 890d???????? | // ffd6 | call esi // 6a00 | push 0 $sequence_3 = { e8???????? 6a01 6a00 6a00 ff15???????? 8bf8 } // n = 6, score = 200 // e8???????? | // 6a01 | push 1 // 6a00 | push 0 // 6a00 | push 0 // ff15???????? | // 8bf8 | mov edi, eax $sequence_4 = { 6a10 8d4ddc 8bf0 51 56 ff15???????? 85c0 } // n = 7, score = 200 // 6a10 | push 0x10 // 8d4ddc | lea ecx, [ebp - 0x24] // 8bf0 | mov esi, eax // 51 | push ecx // 56 | push esi // ff15???????? | // 85c0 | test eax, eax $sequence_5 = { ff15???????? 6a10 8d4ddc 8bf0 } // n = 4, score = 200 // ff15???????? | // 6a10 | push 0x10 // 8d4ddc | lea ecx, [ebp - 0x24] // 8bf0 | mov esi, eax $sequence_6 = { 68???????? 50 c705????????01000000 c705????????00000000 } // n = 4, score = 200 // 68???????? | // 50 | push eax // c705????????01000000 | // c705????????00000000 | $sequence_7 = { 894710 ff15???????? 6a00 6a00 } // n = 4, score = 200 // 894710 | mov dword ptr [edi + 0x10], eax // ff15???????? | // 6a00 | push 0 // 6a00 | push 0 $sequence_8 = { 50 6a02 ff15???????? 6a10 } // n = 4, score = 200 // 50 | push eax // 6a02 | push 2 // ff15???????? | // 6a10 | push 0x10 $sequence_9 = { ffd7 56 ffd7 5e b801000000 } // n = 5, score = 200 // ffd7 | call edi // 56 | push esi // ffd7 | call edi // 5e | pop esi // b801000000 | mov eax, 1 $sequence_10 = { 85f6 7513 8b45d8 8b4818 8b5104 50 } // n = 6, score = 200 // 85f6 | test esi, esi // 7513 | jne 0x15 // 8b45d8 | mov eax, dword ptr [ebp - 0x28] // 8b4818 | mov ecx, dword ptr [eax + 0x18] // 8b5104 | mov edx, dword ptr [ecx + 4] // 50 | push eax $sequence_11 = { 57 ff15???????? 5e 33c0 5f c3 56 } // n = 7, score = 200 // 57 | push edi // ff15???????? | // 5e | pop esi // 33c0 | xor eax, eax // 5f | pop edi // c3 | ret // 56 | push esi $sequence_12 = { 8945e4 8945e8 b802000000 51 668945dc } // n = 5, score = 200 // 8945e4 | mov dword ptr [ebp - 0x1c], eax // 8945e8 | mov dword ptr [ebp - 0x18], eax // b802000000 | mov eax, 2 // 51 | push ecx // 668945dc | mov word ptr [ebp - 0x24], ax $sequence_13 = { 50 ff15???????? 8b0d???????? 8b35???????? 890d???????? } // n = 5, score = 200 // 50 | push eax // ff15???????? | // 8b0d???????? | // 8b35???????? | // 890d???????? | $sequence_14 = { 52 6a00 68ffff1f00 ffd7 8bf0 85f6 } // n = 6, score = 200 // 52 | push edx // 6a00 | push 0 // 68ffff1f00 | push 0x1fffff // ffd7 | call edi // 8bf0 | mov esi, eax // 85f6 | test esi, esi $sequence_15 = { 488d95f8000000 488d4c2460 e8???????? 488b08 48635104 4803d0 f6421006 } // n = 7, score = 100 // 488d95f8000000 | dec eax // 488d4c2460 | mov ecx, ebx // e8???????? | // 488b08 | dec eax // 48635104 | lea edx, [ebp + 0xf8] // 4803d0 | dec eax // f6421006 | lea ecx, [esp + 0x60] $sequence_16 = { 4885db 7473 4c3bcb 776e b801000000 492bc1 } // n = 6, score = 100 // 4885db | cmp dword ptr [esp + 0x98], 0x10 // 7473 | jb 0x18 // 4c3bcb | dec eax // 776e | mov ecx, dword ptr [esp + 0x80] // b801000000 | test bl, bl // 492bc1 | jne 0xfffffe26 $sequence_17 = { 4883bc249800000010 720d 488b8c2480000000 e8???????? 84db 0f8516feffff } // n = 6, score = 100 // 4883bc249800000010 | dec eax // 720d | mov edx, dword ptr [esp + 0x68] // 488b8c2480000000 | dec eax // e8???????? | // 84db | mov ebx, dword ptr [esp + 0x60] // 0f8516feffff | dec eax $sequence_18 = { e8???????? 84c0 7418 488b0b 488d5330 4533c9 } // n = 6, score = 100 // e8???????? | // 84c0 | inc eax // 7418 | push ebx // 488b0b | dec eax // 488d5330 | sub esp, 0x20 // 4533c9 | dec eax $sequence_19 = { e8???????? 48837f1810 48895f10 0f82d2000000 488b07 e9???????? } // n = 6, score = 100 // e8???????? | // 48837f1810 | jb 0x79 // 48895f10 | dec eax // 0f82d2000000 | lea edi, [esp + 0x50] // 488b07 | dec eax // e9???????? | $sequence_20 = { 488b542468 488b5c2460 488b4c2450 4883ceff 4883fb01 726a 488d7c2450 } // n = 7, score = 100 // 488b542468 | dec eax // 488b5c2460 | mov ecx, dword ptr [eax] // 488b4c2450 | dec eax // 4883ceff | arpl word ptr [ecx + 4], dx // 4883fb01 | dec eax // 726a | add edx, eax // 488d7c2450 | test byte ptr [edx + 0x10], 6 $sequence_21 = { 488d15e7330100 483305???????? 488bcb 488905???????? ff15???????? } // n = 5, score = 100 // 488d15e7330100 | dec eax // 483305???????? | // 488bcb | lea edx, [0x133e7] // 488905???????? | // ff15???????? | $sequence_22 = { 4053 4883ec20 488b01 488d9990000000 48634804 } // n = 5, score = 100 // 4053 | mov ecx, dword ptr [esp + 0x50] // 4883ec20 | dec eax // 488b01 | or esi, 0xffffffff // 488d9990000000 | dec eax // 48634804 | cmp ebx, 1 condition: 7 of them and filesize < 614400 }
rule win_remexi_w0 { meta: source = "http://www.symantec.com/content/en/us/enterprise/media/security_response/docs/CadelSpy-Remexi-IOC.pdf" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.remexi" malpedia_version = "20170410" malpedia_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" strings: $c1 = { 00 3C 65 78 69 74 3E 00 } /* <exit> */ $c2 = { 00 3C 69 64 3E 00 } /* <id> */ $c3 = { 00 3C 72 65 6D 3E 00 } /* <rem> */ $c4 = { 00 3C 63 6C 6F 73 65 3E 00} /* <close> */ $c5 = { 00 57 49 4E 00 } /* WIN */ $c6 = { 00 63 6D 64 2E 65 78 65 00 } /* cmd.exe */ $c7 = { 00 49 44 00 } /* ID */ $c8 = { 00 72 65 6D 00 } /* rem */ $d1 = "\\SEA.pdb" $d2 = "\\mas.pdb" $s1 = "Connecting to the server..." $s2 = "cmd.exe /c sc stop sea & sc start sea" $s3 = "SYSTEM\\CurrentControlSet\\services\\SEA\\Parameters" $s4 = "RecvWrit()-Read_Sock-Failed" $s5 = "ReadPipeSendSock()" condition: (4 of ($c*) and (2 of ($s*) or any of ($d*))) or (5 of ($c*) and any of ($s*)) }
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