SYMBOLCOMMON_NAMEaka. SYNONYMS
win.leouncia (Back to overview)

Leouncia

aka: shoco

Actor(s): APT5


There is no description at this point.

References
2010-12-14FireEyeAtif Mushtaq
@online{mushtaq:20101214:leouncia:35e77c5, author = {Atif Mushtaq}, title = {{Leouncia - Yet Another Backdoor - Part 2}}, date = {2010-12-14}, organization = {FireEye}, url = {https://www.fireeye.com/blog/threat-research/2010/12/leouncia-yet-another-backdoor-part-2.html}, language = {English}, urldate = {2019-12-20} } Leouncia - Yet Another Backdoor - Part 2
Leouncia
Yara Rules
[TLP:WHITE] win_leouncia_auto (20220808 | Detects win.leouncia.)
rule win_leouncia_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.leouncia."
        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.leouncia"
        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 = { 740e 0fb70445eaa24000 23442408 eb02 33c0 85c0 }
            // n = 6, score = 100
            //   740e                 | je                  0x10
            //   0fb70445eaa24000     | movzx               eax, word ptr [eax*2 + 0x40a2ea]
            //   23442408             | and                 eax, dword ptr [esp + 8]
            //   eb02                 | jmp                 4
            //   33c0                 | xor                 eax, eax
            //   85c0                 | test                eax, eax

        $sequence_1 = { 56 8b11 8d7010 8954240c 57 8b5104 8bfd }
            // n = 7, score = 100
            //   56                   | push                esi
            //   8b11                 | mov                 edx, dword ptr [ecx]
            //   8d7010               | lea                 esi, [eax + 0x10]
            //   8954240c             | mov                 dword ptr [esp + 0xc], edx
            //   57                   | push                edi
            //   8b5104               | mov                 edx, dword ptr [ecx + 4]
            //   8bfd                 | mov                 edi, ebp

        $sequence_2 = { 7542 8bbc2454040000 33db 8d4c2410 c744241000000000 }
            // n = 5, score = 100
            //   7542                 | jne                 0x44
            //   8bbc2454040000       | mov                 edi, dword ptr [esp + 0x454]
            //   33db                 | xor                 ebx, ebx
            //   8d4c2410             | lea                 ecx, [esp + 0x10]
            //   c744241000000000     | mov                 dword ptr [esp + 0x10], 0

        $sequence_3 = { 55 56 33db 57 8b3d???????? 8d442434 53 }
            // n = 7, score = 100
            //   55                   | push                ebp
            //   56                   | push                esi
            //   33db                 | xor                 ebx, ebx
            //   57                   | push                edi
            //   8b3d????????         |                     
            //   8d442434             | lea                 eax, [esp + 0x34]
            //   53                   | push                ebx

        $sequence_4 = { eb0f 0fb6d2 f68221b0400004 7403 }
            // n = 4, score = 100
            //   eb0f                 | jmp                 0x11
            //   0fb6d2               | movzx               edx, dl
            //   f68221b0400004       | test                byte ptr [edx + 0x40b021], 4
            //   7403                 | je                  5

        $sequence_5 = { ff15???????? 3bc3 740b 83f801 75dd 395c2410 75d7 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   3bc3                 | cmp                 eax, ebx
            //   740b                 | je                  0xd
            //   83f801               | cmp                 eax, 1
            //   75dd                 | jne                 0xffffffdf
            //   395c2410             | cmp                 dword ptr [esp + 0x10], ebx
            //   75d7                 | jne                 0xffffffd9

        $sequence_6 = { 8b4c241c 2bd1 83c404 81fa2c010000 7e21 833d????????03 }
            // n = 6, score = 100
            //   8b4c241c             | mov                 ecx, dword ptr [esp + 0x1c]
            //   2bd1                 | sub                 edx, ecx
            //   83c404               | add                 esp, 4
            //   81fa2c010000         | cmp                 edx, 0x12c
            //   7e21                 | jle                 0x23
            //   833d????????03       |                     

        $sequence_7 = { 8d442424 50 e8???????? 8b4c2428 8b54242c 2bca 83c404 }
            // n = 7, score = 100
            //   8d442424             | lea                 eax, [esp + 0x24]
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b4c2428             | mov                 ecx, dword ptr [esp + 0x28]
            //   8b54242c             | mov                 edx, dword ptr [esp + 0x2c]
            //   2bca                 | sub                 ecx, edx
            //   83c404               | add                 esp, 4

        $sequence_8 = { 52 894c2410 8b542460 894c2414 8d4c2418 51 50 }
            // n = 7, score = 100
            //   52                   | push                edx
            //   894c2410             | mov                 dword ptr [esp + 0x10], ecx
            //   8b542460             | mov                 edx, dword ptr [esp + 0x60]
            //   894c2414             | mov                 dword ptr [esp + 0x14], ecx
            //   8d4c2418             | lea                 ecx, [esp + 0x18]
            //   51                   | push                ecx
            //   50                   | push                eax

        $sequence_9 = { 50 56 c744244028000000 895c2444 895c2448 895c244c 895c2450 }
            // n = 7, score = 100
            //   50                   | push                eax
            //   56                   | push                esi
            //   c744244028000000     | mov                 dword ptr [esp + 0x40], 0x28
            //   895c2444             | mov                 dword ptr [esp + 0x44], ebx
            //   895c2448             | mov                 dword ptr [esp + 0x48], ebx
            //   895c244c             | mov                 dword ptr [esp + 0x4c], ebx
            //   895c2450             | mov                 dword ptr [esp + 0x50], ebx

    condition:
        7 of them and filesize < 114688
}
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