Actor(s): APT33, The Gorgon Group
There is no description at this point.
rule win_remcos_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2020-12-22" version = "1" description = "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.remcos" malpedia_rule_date = "20201222" malpedia_hash = "30354d830a29f0fbd3714d93d94dea941d77a130" malpedia_version = "20201023" 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 = { ff15???????? 8d4d08 ff15???????? 8d4d18 } // n = 4, score = 1400 // ff15???????? | // 8d4d08 | lea ecx, [ebp + 8] // ff15???????? | // 8d4d18 | lea ecx, [ebp + 0x18] $sequence_1 = { 57 ff15???????? 85c0 8945fc 0f84f3000000 837e0400 7551 } // n = 7, score = 1400 // 57 | push edi // ff15???????? | // 85c0 | test eax, eax // 8945fc | mov dword ptr [ebp - 4], eax // 0f84f3000000 | je 0xf9 // 837e0400 | cmp dword ptr [esi + 4], 0 // 7551 | jne 0x53 $sequence_2 = { 8d4df0 e8???????? 8bc8 ff15???????? 50 e8???????? } // n = 6, score = 1400 // 8d4df0 | lea ecx, [ebp - 0x10] // e8???????? | // 8bc8 | mov ecx, eax // ff15???????? | // 50 | push eax // e8???????? | $sequence_3 = { 57 e8???????? 6a01 57 e8???????? 83c414 } // n = 6, score = 1400 // 57 | push edi // e8???????? | // 6a01 | push 1 // 57 | push edi // e8???????? | // 83c414 | add esp, 0x14 $sequence_4 = { 47 ff4d0c 8a4c0bff 8808 803c3700 75d8 5b } // n = 7, score = 1400 // 47 | inc edi // ff4d0c | dec dword ptr [ebp + 0xc] // 8a4c0bff | mov cl, byte ptr [ebx + ecx - 1] // 8808 | mov byte ptr [eax], cl // 803c3700 | cmp byte ptr [edi + esi], 0 // 75d8 | jne 0xffffffda // 5b | pop ebx $sequence_5 = { 50 e8???????? 83c40c 8bce ff7608 50 e8???????? } // n = 7, score = 1400 // 50 | push eax // e8???????? | // 83c40c | add esp, 0xc // 8bce | mov ecx, esi // ff7608 | push dword ptr [esi + 8] // 50 | push eax // e8???????? | $sequence_6 = { 99 f7fb 3bc7 7348 8b4508 } // n = 5, score = 1400 // 99 | cdq // f7fb | idiv ebx // 3bc7 | cmp eax, edi // 7348 | jae 0x4a // 8b4508 | mov eax, dword ptr [ebp + 8] $sequence_7 = { 8d4ddc ff15???????? 5f 5e } // n = 4, score = 1400 // 8d4ddc | lea ecx, [ebp - 0x24] // ff15???????? | // 5f | pop edi // 5e | pop esi $sequence_8 = { 8bf8 ff15???????? 3bf8 729b } // n = 4, score = 1400 // 8bf8 | mov edi, eax // ff15???????? | // 3bf8 | cmp edi, eax // 729b | jb 0xffffff9d $sequence_9 = { 59 740f ff7608 8bc8 ff75fc e8???????? eb02 } // n = 7, score = 1400 // 59 | pop ecx // 740f | je 0x11 // ff7608 | push dword ptr [esi + 8] // 8bc8 | mov ecx, eax // ff75fc | push dword ptr [ebp - 4] // e8???????? | // eb02 | jmp 4 condition: 7 of them and filesize < 368640 }
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