SYMBOLCOMMON_NAMEaka. SYNONYMS
win.wannahusky (Back to overview)

WannaHusky


According to Mars, WannaHusky is a Nim-compiled ransomware malware sample, created for demonstration purposes and provided as part of the Practical Malware Analysis & Triage course provided by HuskyHacks.

References
2022-04-06Medium mars0xMars
@online{mars:20220406:wannahusky:0f8a9a7, author = {Mars}, title = {{WannaHusky Malware Analysis w/ YARA + TTPs}}, date = {2022-04-06}, organization = {Medium mars0x}, url = {https://medium.com/@mars0x/wannahusky-malware-analysis-w-yara-ttps-2069fb479909}, language = {English}, urldate = {2022-04-08} } WannaHusky Malware Analysis w/ YARA + TTPs
WannaHusky
Yara Rules
[TLP:WHITE] win_wannahusky_auto (20220808 | Detects win.wannahusky.)
rule win_wannahusky_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.wannahusky."
        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.wannahusky"
        malpedia_rule_date = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 8d443308 890424 897c2404 e8???????? 85c0 74c3 }
            // n = 6, score = 100
            //   8d443308             | lea                 eax, [ebx + esi + 8]
            //   890424               | mov                 dword ptr [esp], eax
            //   897c2404             | mov                 dword ptr [esp + 4], edi
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   74c3                 | je                  0xffffffc5

        $sequence_1 = { c705????????04000000 c605????????11 c705????????40474200 c705????????c0b54100 }
            // n = 4, score = 100
            //   c705????????04000000     |     
            //   c605????????11       |                     
            //   c705????????40474200     |     
            //   c705????????c0b54100     |     

        $sequence_2 = { c705????????24000000 c705????????c0474200 c705????????eb1d4100 c705????????90b54100 c605????????01 }
            // n = 5, score = 100
            //   c705????????24000000     |     
            //   c705????????c0474200     |     
            //   c705????????eb1d4100     |     
            //   c705????????90b54100     |     
            //   c605????????01       |                     

        $sequence_3 = { 7405 8b08 83c11a e8???????? ba???????? e8???????? }
            // n = 6, score = 100
            //   7405                 | je                  7
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   83c11a               | add                 ecx, 0x1a
            //   e8????????           |                     
            //   ba????????           |                     
            //   e8????????           |                     

        $sequence_4 = { 83c008 c744240401000000 890424 ff15???????? 89ca b9???????? }
            // n = 6, score = 100
            //   83c008               | add                 eax, 8
            //   c744240401000000     | mov                 dword ptr [esp + 4], 1
            //   890424               | mov                 dword ptr [esp], eax
            //   ff15????????         |                     
            //   89ca                 | mov                 edx, ecx
            //   b9????????           |                     

        $sequence_5 = { 66c705????????1101 c605????????01 c705????????2c000000 c705????????80ba4100 c705????????0c1e4100 }
            // n = 5, score = 100
            //   66c705????????1101     |     
            //   c605????????01       |                     
            //   c705????????2c000000     |     
            //   c705????????80ba4100     |     
            //   c705????????0c1e4100     |     

        $sequence_6 = { 8985f4faffff 85f6 7443 8b0e }
            // n = 4, score = 100
            //   8985f4faffff         | mov                 dword ptr [ebp - 0x50c], eax
            //   85f6                 | test                esi, esi
            //   7443                 | je                  0x45
            //   8b0e                 | mov                 ecx, dword ptr [esi]

        $sequence_7 = { 7405 8b08 83c118 e8???????? 8b15???????? }
            // n = 5, score = 100
            //   7405                 | je                  7
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   83c118               | add                 ecx, 0x18
            //   e8????????           |                     
            //   8b15????????         |                     

        $sequence_8 = { 0fb61401 8d4dd4 09d7 ba01000000 0b7dac }
            // n = 5, score = 100
            //   0fb61401             | movzx               edx, byte ptr [ecx + eax]
            //   8d4dd4               | lea                 ecx, [ebp - 0x2c]
            //   09d7                 | or                  edi, edx
            //   ba01000000           | mov                 edx, 1
            //   0b7dac               | or                  edi, dword ptr [ebp - 0x54]

        $sequence_9 = { c705????????14000000 c705????????00484200 c705????????b41d4100 c705????????30b54100 c705????????00000000 c705????????04000000 }
            // n = 6, score = 100
            //   c705????????14000000     |     
            //   c705????????00484200     |     
            //   c705????????b41d4100     |     
            //   c705????????30b54100     |     
            //   c705????????00000000     |     
            //   c705????????04000000     |     

    condition:
        7 of them and filesize < 862208
}
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