SYMBOLCOMMON_NAMEaka. SYNONYMS
win.mindware (Back to overview)

Mindware


Ransomware, potential rebranding of win.sfile.

References
2022-06-06SentinelOneNiranjan Jayanand
@online{jayanand:20220606:from:0fa017a, author = {Niranjan Jayanand}, title = {{From the Front Lines | Another Rebrand? Mindware and SFile Ransomware Technical Breakdown}}, date = {2022-06-06}, organization = {SentinelOne}, url = {https://www.sentinelone.com/blog/from-the-front-lines-another-rebrand-mindware-and-sfile-ransomware-technical-breakdown/}, language = {English}, urldate = {2022-06-09} } From the Front Lines | Another Rebrand? Mindware and SFile Ransomware Technical Breakdown
Mindware Sfile
Yara Rules
[TLP:WHITE] win_mindware_auto (20230125 | Detects win.mindware.)
rule win_mindware_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.mindware."
        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.mindware"
        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 = { c745f4f09b4300 eb1a 33c9 7409 c745f8???????? eb07 c745f8???????? }
            // n = 7, score = 100
            //   c745f4f09b4300       | mov                 dword ptr [ebp - 0xc], 0x439bf0
            //   eb1a                 | jmp                 0x1c
            //   33c9                 | xor                 ecx, ecx
            //   7409                 | je                  0xb
            //   c745f8????????       |                     
            //   eb07                 | jmp                 9
            //   c745f8????????       |                     

        $sequence_1 = { c78528ffffffd8034400 c7852cffffffe0034400 c78530ffffffe8034400 c78534fffffff8034400 c78538ffffff08044400 c7853cffffff10044400 c78540ffffff18044400 }
            // n = 7, score = 100
            //   c78528ffffffd8034400     | mov    dword ptr [ebp - 0xd8], 0x4403d8
            //   c7852cffffffe0034400     | mov    dword ptr [ebp - 0xd4], 0x4403e0
            //   c78530ffffffe8034400     | mov    dword ptr [ebp - 0xd0], 0x4403e8
            //   c78534fffffff8034400     | mov    dword ptr [ebp - 0xcc], 0x4403f8
            //   c78538ffffff08044400     | mov    dword ptr [ebp - 0xc8], 0x440408
            //   c7853cffffff10044400     | mov    dword ptr [ebp - 0xc4], 0x440410
            //   c78540ffffff18044400     | mov    dword ptr [ebp - 0xc0], 0x440418

        $sequence_2 = { c785b4feffff88024400 c785b8feffff90024400 c785bcfeffff98024400 c785c0feffffa0024400 c785c4feffffa8024400 c785c8feffffb0024400 }
            // n = 6, score = 100
            //   c785b4feffff88024400     | mov    dword ptr [ebp - 0x14c], 0x440288
            //   c785b8feffff90024400     | mov    dword ptr [ebp - 0x148], 0x440290
            //   c785bcfeffff98024400     | mov    dword ptr [ebp - 0x144], 0x440298
            //   c785c0feffffa0024400     | mov    dword ptr [ebp - 0x140], 0x4402a0
            //   c785c4feffffa8024400     | mov    dword ptr [ebp - 0x13c], 0x4402a8
            //   c785c8feffffb0024400     | mov    dword ptr [ebp - 0x138], 0x4402b0

        $sequence_3 = { 740a 8b4dc0 51 ff15???????? 33c0 e9???????? }
            // n = 6, score = 100
            //   740a                 | je                  0xc
            //   8b4dc0               | mov                 ecx, dword ptr [ebp - 0x40]
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   33c0                 | xor                 eax, eax
            //   e9????????           |                     

        $sequence_4 = { 33148dc0bc4400 8bcb c1e918 33148dc0c44400 8b4df0 }
            // n = 5, score = 100
            //   33148dc0bc4400       | xor                 edx, dword ptr [ecx*4 + 0x44bcc0]
            //   8bcb                 | mov                 ecx, ebx
            //   c1e918               | shr                 ecx, 0x18
            //   33148dc0c44400       | xor                 edx, dword ptr [ecx*4 + 0x44c4c0]
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]

        $sequence_5 = { 8b4508 83c02c 8945cc 6880000000 6a00 8d8d4cffffff 51 }
            // n = 7, score = 100
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   83c02c               | add                 eax, 0x2c
            //   8945cc               | mov                 dword ptr [ebp - 0x34], eax
            //   6880000000           | push                0x80
            //   6a00                 | push                0
            //   8d8d4cffffff         | lea                 ecx, [ebp - 0xb4]
            //   51                   | push                ecx

        $sequence_6 = { 83c002 8945e8 8b4df4 668b11 668955fe 8345f402 66837dfe00 }
            // n = 7, score = 100
            //   83c002               | add                 eax, 2
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   8b4df4               | mov                 ecx, dword ptr [ebp - 0xc]
            //   668b11               | mov                 dx, word ptr [ecx]
            //   668955fe             | mov                 word ptr [ebp - 2], dx
            //   8345f402             | add                 dword ptr [ebp - 0xc], 2
            //   66837dfe00           | cmp                 word ptr [ebp - 2], 0

        $sequence_7 = { c78574e5ffffb8c34300 c78578e5ffffc0c34300 c7857ce5ffffc8c34300 c78580e5ffffd4c34300 c78584e5ffffe0c34300 c78588e5ffffe8c34300 }
            // n = 6, score = 100
            //   c78574e5ffffb8c34300     | mov    dword ptr [ebp - 0x1a8c], 0x43c3b8
            //   c78578e5ffffc0c34300     | mov    dword ptr [ebp - 0x1a88], 0x43c3c0
            //   c7857ce5ffffc8c34300     | mov    dword ptr [ebp - 0x1a84], 0x43c3c8
            //   c78580e5ffffd4c34300     | mov    dword ptr [ebp - 0x1a80], 0x43c3d4
            //   c78584e5ffffe0c34300     | mov    dword ptr [ebp - 0x1a7c], 0x43c3e0
            //   c78588e5ffffe8c34300     | mov    dword ptr [ebp - 0x1a78], 0x43c3e8

        $sequence_8 = { 0fb6c9 33148dc0c84400 8bcb 33500c c1e910 }
            // n = 5, score = 100
            //   0fb6c9               | movzx               ecx, cl
            //   33148dc0c84400       | xor                 edx, dword ptr [ecx*4 + 0x44c8c0]
            //   8bcb                 | mov                 ecx, ebx
            //   33500c               | xor                 edx, dword ptr [eax + 0xc]
            //   c1e910               | shr                 ecx, 0x10

        $sequence_9 = { 83c201 8955fc 837dfc04 7d12 8b45fc 8b4d08 8b1481 }
            // n = 7, score = 100
            //   83c201               | add                 edx, 1
            //   8955fc               | mov                 dword ptr [ebp - 4], edx
            //   837dfc04             | cmp                 dword ptr [ebp - 4], 4
            //   7d12                 | jge                 0x14
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   8b1481               | mov                 edx, dword ptr [ecx + eax*4]

    condition:
        7 of them and filesize < 661504
}
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