Ransomware written in Go.
rule win_decaf_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.decaf." 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.decaf" malpedia_rule_date = "20230124" malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686" malpedia_version = "20230125" 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 = { 90 4883f82e 7d31 0fb6540442 488d7001 4883fe2e 7355 } // n = 7, score = 100 // 90 | jne 0x8d7 // 4883f82e | dec eax // 7d31 | mov ecx, dword ptr [esp + 0x2b8] // 0fb6540442 | dec eax // 488d7001 | mov dword ptr [esp + 0x3b8], ecx // 4883fe2e | dec eax // 7355 | lea eax, [0x149fdf] $sequence_1 = { eb11 488d7818 488b8c24c0210000 e8???????? 488b4c2478 48894808 833d????????00 } // n = 7, score = 100 // eb11 | dec eax // 488d7818 | lea eax, [0x16c81] // 488b8c24c0210000 | nop // e8???????? | // 488b4c2478 | dec eax // 48894808 | mov dword ptr [esp + 0x18], eax // 833d????????00 | $sequence_2 = { b8d1ffffff 90 ffd1 488b08 4889c2 b833000000 ffd1 } // n = 7, score = 100 // b8d1ffffff | mov eax, dword ptr [esp + 0x40] // 90 | mov word ptr [edi + ebx], 0x222d // ffd1 | dec eax // 488b08 | mov edx, dword ptr [esp + 0x50] // 4889c2 | dec eax // b833000000 | mov ebx, dword ptr [esp + 0x48] // ffd1 | dec esp $sequence_3 = { e8???????? 488d0594bb1400 488b5c2438 488d0ddc151700 bf07000000 0f1f00 e8???????? } // n = 7, score = 100 // e8???????? | // 488d0594bb1400 | mov dword ptr [eax + 8], ecx // 488b5c2438 | jne 0x94 // 488d0ddc151700 | dec eax // bf07000000 | mov ecx, dword ptr [esp + 0x11f8] // 0f1f00 | dec eax // e8???????? | $sequence_4 = { eb0c 488d3dce011700 e8???????? e8???????? 48891d???????? 833d????????00 7509 } // n = 7, score = 100 // eb0c | dec eax // 488d3dce011700 | mov edi, ecx // e8???????? | // e8???????? | // 48891d???????? | // 833d????????00 | // 7509 | mov esi, 0xf $sequence_5 = { 7331 488d053e470600 4889d9 4889fb 4889f7 4c89c6 e8???????? } // n = 7, score = 100 // 7331 | mov edx, 0x10789e6f // 488d053e470600 | add bh, byte ptr [eax - 0x76b7ba4b] // 4889d9 | push esp // 4889fb | and al, 0x68 // 4889f7 | movzx edx, byte ptr [esp + 0x61] // 4c89c6 | mov byte ptr [esp + 0x59], dl // e8???????? | $sequence_6 = { 90 c7442459aef5ccc5 0fb654245a 88542445 440fb644245c 4488442444 440fb64c245b } // n = 7, score = 100 // 90 | test edx, edx // c7442459aef5ccc5 | jle 0x7de // 0fb654245a | dec eax // 88542445 | mov dword ptr [esp + 0x28], edx // 440fb644245c | xor eax, eax // 4488442444 | nop // 440fb64c245b | jne 0x7e4 $sequence_7 = { c78424b2000000fa653403 66c78424b60000004496 0fb69424b5000000 88542450 440fb68424b3000000 448844244f 440fb68c24b7000000 } // n = 7, score = 100 // c78424b2000000fa653403 | dec eax // 66c78424b60000004496 | lea eax, [0x19c5cb] // 0fb69424b5000000 | dec eax // 88542450 | mov dword ptr [esp], eax // 440fb68424b3000000 | dec eax // 448844244f | mov esi, dword ptr [esp + 0x60] // 440fb68c24b7000000 | dec eax $sequence_8 = { ba05000000 488d3de5f11800 eb08 488bbc2428020000 4889f8 4889d3 e8???????? } // n = 7, score = 100 // ba05000000 | dec eax // 488d3de5f11800 | mov eax, dword ptr [esp + 0x48] // eb08 | mov byte ptr [edi + ebx], 0xf9 // 488bbc2428020000 | xor ecx, ecx // 4889f8 | dec eax // 4889d3 | mov edx, dword ptr [esp + 0x58] // e8???????? | $sequence_9 = { e8???????? 6690 4885c9 7560 488b8c24d8010000 bf10000000 4889fe } // n = 7, score = 100 // e8???????? | // 6690 | mov ebx, dword ptr [edi + 0x18] // 4885c9 | dec eax // 7560 | lea eax, [0x14f379] // 488b8c24d8010000 | dec eax // bf10000000 | mov edx, dword ptr [esp + 0xa8] // 4889fe | dec eax condition: 7 of them and filesize < 7193600 }
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