SYMBOLCOMMON_NAMEaka. SYNONYMS
win.joao (Back to overview)

Joao


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References
2017-08-22ESET ResearchTomáš Gardoň
@online{gardo:20170822:gamescom:764a8eb, author = {Tomáš Gardoň}, title = {{Gamescom 2017: It’s all fun and games until black hats step in}}, date = {2017-08-22}, organization = {ESET Research}, url = {https://www.welivesecurity.com/2017/08/22/gamescom-2017-fun-blackhats/}, language = {English}, urldate = {2019-11-14} } Gamescom 2017: It’s all fun and games until black hats step in
Joao
Yara Rules
[TLP:WHITE] win_joao_auto (20230715 | Detects win.joao.)
rule win_joao_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.joao."
        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.joao"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { 8d45d4 52 51 50 }
            // n = 4, score = 400
            //   8d45d4               | lea                 eax, [ebp - 0x2c]
            //   52                   | push                edx
            //   51                   | push                ecx
            //   50                   | push                eax

        $sequence_1 = { 3bc7 741e 8b4dfc 51 8b4e08 8d5610 }
            // n = 6, score = 400
            //   3bc7                 | cmp                 eax, edi
            //   741e                 | je                  0x20
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   51                   | push                ecx
            //   8b4e08               | mov                 ecx, dword ptr [esi + 8]
            //   8d5610               | lea                 edx, [esi + 0x10]

        $sequence_2 = { 6a00 8d4dec 51 6a00 52 ffd0 }
            // n = 6, score = 400
            //   6a00                 | push                0
            //   8d4dec               | lea                 ecx, [ebp - 0x14]
            //   51                   | push                ecx
            //   6a00                 | push                0
            //   52                   | push                edx
            //   ffd0                 | call                eax

        $sequence_3 = { 41 51 6a00 56 894510 ffd0 }
            // n = 6, score = 400
            //   41                   | inc                 ecx
            //   51                   | push                ecx
            //   6a00                 | push                0
            //   56                   | push                esi
            //   894510               | mov                 dword ptr [ebp + 0x10], eax
            //   ffd0                 | call                eax

        $sequence_4 = { 8845d4 c745fc01000000 84c0 0f84dc000000 8b16 }
            // n = 5, score = 400
            //   8845d4               | mov                 byte ptr [ebp - 0x2c], al
            //   c745fc01000000       | mov                 dword ptr [ebp - 4], 1
            //   84c0                 | test                al, al
            //   0f84dc000000         | je                  0xe2
            //   8b16                 | mov                 edx, dword ptr [esi]

        $sequence_5 = { 8d45d0 50 8bce 897dfc e8???????? 837de810 c745fcffffffff }
            // n = 7, score = 400
            //   8d45d0               | lea                 eax, [ebp - 0x30]
            //   50                   | push                eax
            //   8bce                 | mov                 ecx, esi
            //   897dfc               | mov                 dword ptr [ebp - 4], edi
            //   e8????????           |                     
            //   837de810             | cmp                 dword ptr [ebp - 0x18], 0x10
            //   c745fcffffffff       | mov                 dword ptr [ebp - 4], 0xffffffff

        $sequence_6 = { 8b4804 8b4c3138 c645ef01 4b }
            // n = 4, score = 400
            //   8b4804               | mov                 ecx, dword ptr [eax + 4]
            //   8b4c3138             | mov                 ecx, dword ptr [ecx + esi + 0x38]
            //   c645ef01             | mov                 byte ptr [ebp - 0x11], 1
            //   4b                   | dec                 ebx

        $sequence_7 = { 83c40c 85c0 7514 8b45e4 3bc7 }
            // n = 5, score = 400
            //   83c40c               | add                 esp, 0xc
            //   85c0                 | test                eax, eax
            //   7514                 | jne                 0x16
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   3bc7                 | cmp                 eax, edi

        $sequence_8 = { 894510 83c720 e9???????? 8b4df4 }
            // n = 4, score = 400
            //   894510               | mov                 dword ptr [ebp + 0x10], eax
            //   83c720               | add                 edi, 0x20
            //   e9????????           |                     
            //   8b4df4               | mov                 ecx, dword ptr [ebp - 0xc]

        $sequence_9 = { 897e18 897e1c 8b4604 3bc7 741e 8b4dfc }
            // n = 6, score = 400
            //   897e18               | mov                 dword ptr [esi + 0x18], edi
            //   897e1c               | mov                 dword ptr [esi + 0x1c], edi
            //   8b4604               | mov                 eax, dword ptr [esi + 4]
            //   3bc7                 | cmp                 eax, edi
            //   741e                 | je                  0x20
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]

    condition:
        7 of them and filesize < 2867200
}
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