SYMBOLCOMMON_NAMEaka. SYNONYMS
win.final1stspy (Back to overview)

Final1stSpy

Actor(s): APT37


There is no description at this point.

References
2018-10-03IntezerJay Rosenberg
@online{rosenberg:20181003:apt37:93a9100, author = {Jay Rosenberg}, title = {{APT37: Final1stspy Reaping the FreeMilk}}, date = {2018-10-03}, organization = {Intezer}, url = {https://www.intezer.com/apt37-final1stspy-reaping-the-freemilk/}, language = {English}, urldate = {2020-01-09} } APT37: Final1stspy Reaping the FreeMilk
Final1stSpy RokRAT
Yara Rules
[TLP:WHITE] win_final1stspy_auto (20230125 | Detects win.final1stspy.)
rule win_final1stspy_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.final1stspy."
        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.final1stspy"
        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 = { 8a1439 80c27a 80f219 881439 41 3bce 7cef }
            // n = 7, score = 300
            //   8a1439               | mov                 dl, byte ptr [ecx + edi]
            //   80c27a               | add                 dl, 0x7a
            //   80f219               | xor                 dl, 0x19
            //   881439               | mov                 byte ptr [ecx + edi], dl
            //   41                   | inc                 ecx
            //   3bce                 | cmp                 ecx, esi
            //   7cef                 | jl                  0xfffffff1

        $sequence_1 = { 78dc 8b55fc b9???????? c1e006 8a7201 8ad3 3ad6 }
            // n = 7, score = 300
            //   78dc                 | js                  0xffffffde
            //   8b55fc               | mov                 edx, dword ptr [ebp - 4]
            //   b9????????           |                     
            //   c1e006               | shl                 eax, 6
            //   8a7201               | mov                 dh, byte ptr [edx + 1]
            //   8ad3                 | mov                 dl, bl
            //   3ad6                 | cmp                 dl, dh

        $sequence_2 = { e8???????? 8bf8 81e7ff070080 7908 }
            // n = 4, score = 300
            //   e8????????           |                     
            //   8bf8                 | mov                 edi, eax
            //   81e7ff070080         | and                 edi, 0x800007ff
            //   7908                 | jns                 0xa

        $sequence_3 = { 83c8ff 5b 8be5 5d c3 2d???????? 78b0 }
            // n = 7, score = 300
            //   83c8ff               | or                  eax, 0xffffffff
            //   5b                   | pop                 ebx
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   2d????????           |                     
            //   78b0                 | js                  0xffffffb2

        $sequence_4 = { 80f219 881439 41 3bce 7cef 8bc7 }
            // n = 6, score = 300
            //   80f219               | xor                 dl, 0x19
            //   881439               | mov                 byte ptr [ecx + edi], dl
            //   41                   | inc                 ecx
            //   3bce                 | cmp                 ecx, esi
            //   7cef                 | jl                  0xfffffff1
            //   8bc7                 | mov                 eax, edi

        $sequence_5 = { 3bf7 7cf6 8b3d???????? be00020000 6810270000 }
            // n = 5, score = 300
            //   3bf7                 | cmp                 esi, edi
            //   7cf6                 | jl                  0xfffffff8
            //   8b3d????????         |                     
            //   be00020000           | mov                 esi, 0x200
            //   6810270000           | push                0x2710

        $sequence_6 = { 7412 8a5101 41 84d2 75f4 }
            // n = 5, score = 300
            //   7412                 | je                  0x14
            //   8a5101               | mov                 dl, byte ptr [ecx + 1]
            //   41                   | inc                 ecx
            //   84d2                 | test                dl, dl
            //   75f4                 | jne                 0xfffffff6

        $sequence_7 = { 7507 bf01000000 eb2b b8???????? 8acb }
            // n = 5, score = 300
            //   7507                 | jne                 9
            //   bf01000000           | mov                 edi, 1
            //   eb2b                 | jmp                 0x2d
            //   b8????????           |                     
            //   8acb                 | mov                 cl, bl

        $sequence_8 = { 81cf00f8ffff 47 33f6 85ff 7e0a e8???????? }
            // n = 6, score = 300
            //   81cf00f8ffff         | or                  edi, 0xfffff800
            //   47                   | inc                 edi
            //   33f6                 | xor                 esi, esi
            //   85ff                 | test                edi, edi
            //   7e0a                 | jle                 0xc
            //   e8????????           |                     

        $sequence_9 = { 84d2 75f4 5f 5e 83c8ff 5b 8be5 }
            // n = 7, score = 300
            //   84d2                 | test                dl, dl
            //   75f4                 | jne                 0xfffffff6
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   83c8ff               | or                  eax, 0xffffffff
            //   5b                   | pop                 ebx
            //   8be5                 | mov                 esp, ebp

    condition:
        7 of them and filesize < 557056
}
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