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 (20230125 | Detects win.joao.)
rule win_joao_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        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 = "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 = { 7452 8b08 03ce 8bc1 8d7801 }
            // n = 5, score = 400
            //   7452                 | je                  0x54
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   03ce                 | add                 ecx, esi
            //   8bc1                 | mov                 eax, ecx
            //   8d7801               | lea                 edi, [eax + 1]

        $sequence_1 = { 56 57 8bf9 85d2 746b 8b4710 85c0 }
            // n = 7, score = 400
            //   56                   | push                esi
            //   57                   | push                edi
            //   8bf9                 | mov                 edi, ecx
            //   85d2                 | test                edx, edx
            //   746b                 | je                  0x6d
            //   8b4710               | mov                 eax, dword ptr [edi + 0x10]
            //   85c0                 | test                eax, eax

        $sequence_2 = { 51 52 53 e8???????? 83c40c 85c0 74de }
            // n = 7, score = 400
            //   51                   | push                ecx
            //   52                   | push                edx
            //   53                   | push                ebx
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   85c0                 | test                eax, eax
            //   74de                 | je                  0xffffffe0

        $sequence_3 = { 5d c20c00 68???????? 53 }
            // n = 4, score = 400
            //   5d                   | pop                 ebp
            //   c20c00               | ret                 0xc
            //   68????????           |                     
            //   53                   | push                ebx

        $sequence_4 = { 8bf1 ff15???????? 8b7d10 8bd8 85ff }
            // n = 5, score = 400
            //   8bf1                 | mov                 esi, ecx
            //   ff15????????         |                     
            //   8b7d10               | mov                 edi, dword ptr [ebp + 0x10]
            //   8bd8                 | mov                 ebx, eax
            //   85ff                 | test                edi, edi

        $sequence_5 = { 51 8bce c745f807000000 897dfc e8???????? 8d55f8 52 }
            // n = 7, score = 400
            //   51                   | push                ecx
            //   8bce                 | mov                 ecx, esi
            //   c745f807000000       | mov                 dword ptr [ebp - 8], 7
            //   897dfc               | mov                 dword ptr [ebp - 4], edi
            //   e8????????           |                     
            //   8d55f8               | lea                 edx, [ebp - 8]
            //   52                   | push                edx

        $sequence_6 = { 8b31 57 2bc6 bfffffff07 c1f805 2bfa 3bf8 }
            // n = 7, score = 400
            //   8b31                 | mov                 esi, dword ptr [ecx]
            //   57                   | push                edi
            //   2bc6                 | sub                 eax, esi
            //   bfffffff07           | mov                 edi, 0x7ffffff
            //   c1f805               | sar                 eax, 5
            //   2bfa                 | sub                 edi, edx
            //   3bf8                 | cmp                 edi, eax

        $sequence_7 = { 8b7d08 895df8 eb03 8a4dff }
            // n = 4, score = 400
            //   8b7d08               | mov                 edi, dword ptr [ebp + 8]
            //   895df8               | mov                 dword ptr [ebp - 8], ebx
            //   eb03                 | jmp                 5
            //   8a4dff               | mov                 cl, byte ptr [ebp - 1]

        $sequence_8 = { 8b7d08 68???????? ff15???????? 8bf0 68???????? 56 }
            // n = 6, score = 400
            //   8b7d08               | mov                 edi, dword ptr [ebp + 8]
            //   68????????           |                     
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax
            //   68????????           |                     
            //   56                   | push                esi

        $sequence_9 = { e8???????? 83c404 bf09000000 b8???????? 897dd0 c745e80f000000 }
            // n = 6, score = 400
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   bf09000000           | mov                 edi, 9
            //   b8????????           |                     
            //   897dd0               | mov                 dword ptr [ebp - 0x30], edi
            //   c745e80f000000       | mov                 dword ptr [ebp - 0x18], 0xf

    condition:
        7 of them and filesize < 2867200
}
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