Actor(s): Anunak
There is no description at this point.
rule win_jssloader_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-03-28" version = "1" description = "Detects win.jssloader." 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.jssloader" malpedia_rule_date = "20230328" malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d" malpedia_version = "20230407" 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 = { 83f81f 0f8703060000 51 56 e8???????? 83c408 c745d800000000 } // n = 7, score = 200 // 83f81f | cmp eax, 0x1f // 0f8703060000 | ja 0x609 // 51 | push ecx // 56 | push esi // e8???????? | // 83c408 | add esp, 8 // c745d800000000 | mov dword ptr [ebp - 0x28], 0 $sequence_1 = { 74c7 8b45f8 8bce 83e63f c1f906 6bf638 8b0c8d701d4400 } // n = 7, score = 200 // 74c7 | je 0xffffffc9 // 8b45f8 | mov eax, dword ptr [ebp - 8] // 8bce | mov ecx, esi // 83e63f | and esi, 0x3f // c1f906 | sar ecx, 6 // 6bf638 | imul esi, esi, 0x38 // 8b0c8d701d4400 | mov ecx, dword ptr [ecx*4 + 0x441d70] $sequence_2 = { c70600000000 c7460400000000 c7462c00000000 c6463000 e8???????? 6a00 } // n = 6, score = 200 // c70600000000 | mov dword ptr [esi], 0 // c7460400000000 | mov dword ptr [esi + 4], 0 // c7462c00000000 | mov dword ptr [esi + 0x2c], 0 // c6463000 | mov byte ptr [esi + 0x30], 0 // e8???????? | // 6a00 | push 0 $sequence_3 = { 0f4395acfdffff 8bc8 e8???????? ba???????? 8bc8 e8???????? ba???????? } // n = 7, score = 200 // 0f4395acfdffff | cmovae edx, dword ptr [ebp - 0x254] // 8bc8 | mov ecx, eax // e8???????? | // ba???????? | // 8bc8 | mov ecx, eax // e8???????? | // ba???????? | $sequence_4 = { e8???????? 8d4da8 c645fc01 51 8bd0 8d4dd8 e8???????? } // n = 7, score = 200 // e8???????? | // 8d4da8 | lea ecx, [ebp - 0x58] // c645fc01 | mov byte ptr [ebp - 4], 1 // 51 | push ecx // 8bd0 | mov edx, eax // 8d4dd8 | lea ecx, [ebp - 0x28] // e8???????? | $sequence_5 = { 660fd645e4 8dbd48fbffff 8975e4 8975e8 c745ec94214400 c645fc32 } // n = 6, score = 200 // 660fd645e4 | movq qword ptr [ebp - 0x1c], xmm0 // 8dbd48fbffff | lea edi, [ebp - 0x4b8] // 8975e4 | mov dword ptr [ebp - 0x1c], esi // 8975e8 | mov dword ptr [ebp - 0x18], esi // c745ec94214400 | mov dword ptr [ebp - 0x14], 0x442194 // c645fc32 | mov byte ptr [ebp - 4], 0x32 $sequence_6 = { 8bff 55 8bec a1???????? 3b05???????? 0f85c1fbffff } // n = 6, score = 200 // 8bff | mov edi, edi // 55 | push ebp // 8bec | mov ebp, esp // a1???????? | // 3b05???????? | // 0f85c1fbffff | jne 0xfffffbc7 $sequence_7 = { 83c1f4 3b4108 7407 8810 ff4104 eb07 } // n = 6, score = 200 // 83c1f4 | add ecx, -0xc // 3b4108 | cmp eax, dword ptr [ecx + 8] // 7407 | je 9 // 8810 | mov byte ptr [eax], dl // ff4104 | inc dword ptr [ecx + 4] // eb07 | jmp 9 $sequence_8 = { 0f8749020000 52 51 e8???????? 83c408 8d8d6cfcffff } // n = 6, score = 200 // 0f8749020000 | ja 0x24f // 52 | push edx // 51 | push ecx // e8???????? | // 83c408 | add esp, 8 // 8d8d6cfcffff | lea ecx, [ebp - 0x394] $sequence_9 = { 8b4804 8d41f8 89840df4feffff 8d8560ffffff c645fc07 50 c78560ffffffe40e4300 } // n = 7, score = 200 // 8b4804 | mov ecx, dword ptr [eax + 4] // 8d41f8 | lea eax, [ecx - 8] // 89840df4feffff | mov dword ptr [ebp + ecx - 0x10c], eax // 8d8560ffffff | lea eax, [ebp - 0xa0] // c645fc07 | mov byte ptr [ebp - 4], 7 // 50 | push eax // c78560ffffffe40e4300 | mov dword ptr [ebp - 0xa0], 0x430ee4 condition: 7 of them and filesize < 581632 }
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