SYMBOLCOMMON_NAMEaka. SYNONYMS
win.lightbunny (Back to overview)

LIGHTBUNNY


There is no description at this point.

References
2023-03-23MandiantRyan Tomcik, Rufus Brown, Josh Fleischer
@online{tomcik:20230323:unc961:68bbb35, author = {Ryan Tomcik and Rufus Brown and Josh Fleischer}, title = {{UNC961 in the Multiverse of Mandiant: Three Encounters with a Financially Motivated Threat Actor}}, date = {2023-03-23}, organization = {Mandiant}, url = {https://www.mandiant.com/resources/blog/unc961-multiverse-financially-motivated}, language = {English}, urldate = {2023-04-25} } UNC961 in the Multiverse of Mandiant: Three Encounters with a Financially Motivated Threat Actor
HOLERUN LIGHTBUNNY
Yara Rules
[TLP:WHITE] win_lightbunny_auto (20230715 | Detects win.lightbunny.)
rule win_lightbunny_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.lightbunny."
        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.lightbunny"
        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 = { 90 8b45e4 6a00 56 }
            // n = 4, score = 100
            //   90                   | nop                 
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   6a00                 | push                0
            //   56                   | push                esi

        $sequence_1 = { 3bc8 7532 68???????? e8???????? }
            // n = 4, score = 100
            //   3bc8                 | cmp                 ecx, eax
            //   7532                 | jne                 0x34
            //   68????????           |                     
            //   e8????????           |                     

        $sequence_2 = { c7861c10000000000000 81c624100000 81fe???????? 0f8c0effffff 5f 5e b801000000 }
            // n = 7, score = 100
            //   c7861c10000000000000     | mov    dword ptr [esi + 0x101c], 0
            //   81c624100000         | add                 esi, 0x1024
            //   81fe????????         |                     
            //   0f8c0effffff         | jl                  0xffffff14
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   b801000000           | mov                 eax, 1

        $sequence_3 = { 83c404 8bf8 0fb7460c 50 ff7608 }
            // n = 5, score = 100
            //   83c404               | add                 esp, 4
            //   8bf8                 | mov                 edi, eax
            //   0fb7460c             | movzx               eax, word ptr [esi + 0xc]
            //   50                   | push                eax
            //   ff7608               | push                dword ptr [esi + 8]

        $sequence_4 = { 741e 0524100000 41 3d???????? 7cef 5f }
            // n = 6, score = 100
            //   741e                 | je                  0x20
            //   0524100000           | add                 eax, 0x1024
            //   41                   | inc                 ecx
            //   3d????????           |                     
            //   7cef                 | jl                  0xfffffff1
            //   5f                   | pop                 edi

        $sequence_5 = { 33c5 8945fc 56 8bf1 8d95fcfeffff }
            // n = 5, score = 100
            //   33c5                 | xor                 eax, ebp
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   8d95fcfeffff         | lea                 edx, [ebp - 0x104]

        $sequence_6 = { 85db 7507 c746349c3a4100 57 ff7634 }
            // n = 5, score = 100
            //   85db                 | test                ebx, ebx
            //   7507                 | jne                 9
            //   c746349c3a4100       | mov                 dword ptr [esi + 0x34], 0x413a9c
            //   57                   | push                edi
            //   ff7634               | push                dword ptr [esi + 0x34]

        $sequence_7 = { 0f85d2000000 80bdfdfeffff01 0f85c5000000 8b85fffeffff 57 }
            // n = 5, score = 100
            //   0f85d2000000         | jne                 0xd8
            //   80bdfdfeffff01       | cmp                 byte ptr [ebp - 0x103], 1
            //   0f85c5000000         | jne                 0xcb
            //   8b85fffeffff         | mov                 eax, dword ptr [ebp - 0x101]
            //   57                   | push                edi

        $sequence_8 = { 81fe???????? 0f8c0effffff 5f 5e }
            // n = 4, score = 100
            //   81fe????????         |                     
            //   0f8c0effffff         | jl                  0xffffff14
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_9 = { 8b148520ae4100 8a4c1a2d f6c104 7419 8a441a2e 80e1fb }
            // n = 6, score = 100
            //   8b148520ae4100       | mov                 edx, dword ptr [eax*4 + 0x41ae20]
            //   8a4c1a2d             | mov                 cl, byte ptr [edx + ebx + 0x2d]
            //   f6c104               | test                cl, 4
            //   7419                 | je                  0x1b
            //   8a441a2e             | mov                 al, byte ptr [edx + ebx + 0x2e]
            //   80e1fb               | and                 cl, 0xfb

    condition:
        7 of them and filesize < 2376704
}
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