Vidar is a forked malware based on Arkei. It seems this stealer is one of the first that is grabbing information on 2FA Software and Tor Browser.
rule win_vidar_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-03-28" version = "1" description = "Detects win.vidar." 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.vidar" 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 = { c1e810 25ff7f0000 c3 e8???????? } // n = 4, score = 2000 // c1e810 | shr eax, 0x10 // 25ff7f0000 | and eax, 0x7fff // c3 | ret // e8???????? | $sequence_1 = { 740a b800000500 e9???????? 57 } // n = 4, score = 2000 // 740a | je 0xc // b800000500 | mov eax, 0x50000 // e9???????? | // 57 | push edi $sequence_2 = { 8b742408 8b865caf0100 57 83f808 } // n = 4, score = 2000 // 8b742408 | mov esi, dword ptr [esp + 8] // 8b865caf0100 | mov eax, dword ptr [esi + 0x1af5c] // 57 | push edi // 83f808 | cmp eax, 8 $sequence_3 = { c6043300 8bc6 5e 5b c20400 } // n = 5, score = 2000 // c6043300 | mov byte ptr [ebx + esi], 0 // 8bc6 | mov eax, esi // 5e | pop esi // 5b | pop ebx // c20400 | ret 4 $sequence_4 = { c9 c3 8b542408 85d2 7503 33c0 } // n = 6, score = 1900 // c9 | leave // c3 | ret // 8b542408 | mov edx, dword ptr [esp + 8] // 85d2 | test edx, edx // 7503 | jne 5 // 33c0 | xor eax, eax $sequence_5 = { 5e c20400 ff742408 e8???????? 59 83f8ff 7503 } // n = 7, score = 1900 // 5e | pop esi // c20400 | ret 4 // ff742408 | push dword ptr [esp + 8] // e8???????? | // 59 | pop ecx // 83f8ff | cmp eax, -1 // 7503 | jne 5 $sequence_6 = { e8???????? 8b4638 83c410 33c9 3bc3 } // n = 5, score = 1900 // e8???????? | // 8b4638 | mov eax, dword ptr [esi + 0x38] // 83c410 | add esp, 0x10 // 33c9 | xor ecx, ecx // 3bc3 | cmp eax, ebx $sequence_7 = { e8???????? 83c418 53 68???????? 53 } // n = 5, score = 1900 // e8???????? | // 83c418 | add esp, 0x18 // 53 | push ebx // 68???????? | // 53 | push ebx $sequence_8 = { 75f8 be???????? 66a5 ff45ac } // n = 4, score = 1800 // 75f8 | jne 0xfffffffa // be???????? | // 66a5 | movsw word ptr es:[edi], word ptr [esi] // ff45ac | inc dword ptr [ebp - 0x54] $sequence_9 = { 8a10 40 3ad3 75f9 2b450c } // n = 5, score = 1800 // 8a10 | mov dl, byte ptr [eax] // 40 | inc eax // 3ad3 | cmp dl, bl // 75f9 | jne 0xfffffffb // 2b450c | sub eax, dword ptr [ebp + 0xc] $sequence_10 = { 8910 8b4120 8910 8b4130 8910 c3 56 } // n = 7, score = 1700 // 8910 | mov dword ptr [eax], edx // 8b4120 | mov eax, dword ptr [ecx + 0x20] // 8910 | mov dword ptr [eax], edx // 8b4130 | mov eax, dword ptr [ecx + 0x30] // 8910 | mov dword ptr [eax], edx // c3 | ret // 56 | push esi $sequence_11 = { 0faf450c 50 e8???????? 59 } // n = 4, score = 1700 // 0faf450c | imul eax, dword ptr [ebp + 0xc] // 50 | push eax // e8???????? | // 59 | pop ecx $sequence_12 = { c20400 56 8bf1 e8???????? 6a00 ff74240c 8bce } // n = 7, score = 1700 // c20400 | ret 4 // 56 | push esi // 8bf1 | mov esi, ecx // e8???????? | // 6a00 | push 0 // ff74240c | push dword ptr [esp + 0xc] // 8bce | mov ecx, esi $sequence_13 = { 8b4508 8906 8b450c 894608 } // n = 4, score = 1700 // 8b4508 | mov eax, dword ptr [ebp + 8] // 8906 | mov dword ptr [esi], eax // 8b450c | mov eax, dword ptr [ebp + 0xc] // 894608 | mov dword ptr [esi + 8], eax $sequence_14 = { e8???????? 83c408 84c0 740e 68???????? } // n = 5, score = 300 // e8???????? | // 83c408 | add esp, 8 // 84c0 | test al, al // 740e | je 0x10 // 68???????? | $sequence_15 = { 84c9 75f9 8b4c2410 2bc6 50 52 e8???????? } // n = 7, score = 300 // 84c9 | test cl, cl // 75f9 | jne 0xfffffffb // 8b4c2410 | mov ecx, dword ptr [esp + 0x10] // 2bc6 | sub eax, esi // 50 | push eax // 52 | push edx // e8???????? | $sequence_16 = { 83ec08 dd4508 dd1c24 6a0b } // n = 4, score = 200 // 83ec08 | sub esp, 8 // dd4508 | fld qword ptr [ebp + 8] // dd1c24 | fstp qword ptr [esp] // 6a0b | push 0xb $sequence_17 = { 6a0b 6a08 e8???????? 83c41c } // n = 4, score = 200 // 6a0b | push 0xb // 6a08 | push 8 // e8???????? | // 83c41c | add esp, 0x1c $sequence_18 = { 8bb42498090000 89942474090000 2bf0 6a00 56 ffb4248c090000 } // n = 6, score = 100 // 8bb42498090000 | mov esi, dword ptr [esp + 0x998] // 89942474090000 | mov dword ptr [esp + 0x974], edx // 2bf0 | sub esi, eax // 6a00 | push 0 // 56 | push esi // ffb4248c090000 | push dword ptr [esp + 0x98c] $sequence_19 = { 8bb4249c090000 8b842490090000 0fb7fe c1ee10 } // n = 4, score = 100 // 8bb4249c090000 | mov esi, dword ptr [esp + 0x99c] // 8b842490090000 | mov eax, dword ptr [esp + 0x990] // 0fb7fe | movzx edi, si // c1ee10 | shr esi, 0x10 condition: 7 of them and filesize < 2793472 }
rule win_vidar_w0 { meta: description = "Yara rule for detecting Vidar stealer" author = "Fumik0_" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.vidar" malpedia_version = "20190106" malpedia_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" strings: $s1 = { 56 69 64 61 72 } $s2 = { 31 42 45 46 30 41 35 37 42 45 31 31 30 46 44 34 36 37 41 } condition: all of them }
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
