SYMBOLCOMMON_NAMEaka. SYNONYMS
win.unidentified_090 (Back to overview)

Unidentified 090 (Lazarus)

Actor(s): Lazarus Group


Recon/Loader malware attributed to Lazarus, disguised as Notepad++ shell extension.

References
2022-01-31Cyber GeeksVlad Pasca
@online{pasca:20220131:detailed:262ea52, author = {Vlad Pasca}, title = {{A Detailed Analysis Of Lazarus APT Malware Disguised As Notepad++ Shell Extension}}, date = {2022-01-31}, organization = {Cyber Geeks}, url = {https://cybergeeks.tech/a-detailed-analysis-of-lazarus-malware-disguised-as-notepad-shell-extension/}, language = {English}, urldate = {2022-02-02} } A Detailed Analysis Of Lazarus APT Malware Disguised As Notepad++ Shell Extension
Unidentified 090 (Lazarus)
2021-09-06cocomelonccocomelonc
@online{cocomelonc:20210906:av:215e5aa, author = {cocomelonc}, title = {{AV engines evasion for C++ simple malware: part 2}}, date = {2021-09-06}, organization = {cocomelonc}, url = {https://cocomelonc.github.io/tutorial/2021/09/06/simple-malware-av-evasion-2.html}, language = {English}, urldate = {2022-11-28} } AV engines evasion for C++ simple malware: part 2
Agent Tesla Amadey Anchor Carbanak Carberp Cardinal RAT Felixroot Konni Loki Password Stealer (PWS) Maze Unidentified 090 (Lazarus)
Yara Rules
[TLP:WHITE] win_unidentified_090_auto (20230407 | Detects win.unidentified_090.)
rule win_unidentified_090_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.unidentified_090."
        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.unidentified_090"
        malpedia_rule_date = "20230328"
        malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d"
        malpedia_version = "20230407"
        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 = { ff15???????? 85c0 7416 8b4d98 8d458c 50 ff75a0 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7416                 | je                  0x18
            //   8b4d98               | mov                 ecx, dword ptr [ebp - 0x68]
            //   8d458c               | lea                 eax, [ebp - 0x74]
            //   50                   | push                eax
            //   ff75a0               | push                dword ptr [ebp - 0x60]

        $sequence_1 = { 2bc6 898d6cf7ffff 89b588f7ffff 3bd0 7747 83bdacf7ffff08 }
            // n = 6, score = 100
            //   2bc6                 | sub                 eax, esi
            //   898d6cf7ffff         | mov                 dword ptr [ebp - 0x894], ecx
            //   89b588f7ffff         | mov                 dword ptr [ebp - 0x878], esi
            //   3bd0                 | cmp                 edx, eax
            //   7747                 | ja                  0x49
            //   83bdacf7ffff08       | cmp                 dword ptr [ebp - 0x854], 8

        $sequence_2 = { 755f 8bcf 8d5102 668b01 83c102 6685c0 75f5 }
            // n = 7, score = 100
            //   755f                 | jne                 0x61
            //   8bcf                 | mov                 ecx, edi
            //   8d5102               | lea                 edx, [ecx + 2]
            //   668b01               | mov                 ax, word ptr [ecx]
            //   83c102               | add                 ecx, 2
            //   6685c0               | test                ax, ax
            //   75f5                 | jne                 0xfffffff7

        $sequence_3 = { 880a 42 8b0f 83f902 7621 0fb64602 8a8828500210 }
            // n = 7, score = 100
            //   880a                 | mov                 byte ptr [edx], cl
            //   42                   | inc                 edx
            //   8b0f                 | mov                 ecx, dword ptr [edi]
            //   83f902               | cmp                 ecx, 2
            //   7621                 | jbe                 0x23
            //   0fb64602             | movzx               eax, byte ptr [esi + 2]
            //   8a8828500210         | mov                 cl, byte ptr [eax + 0x10025028]

        $sequence_4 = { 8d8d58ffffff e8???????? 83f8ff 0f8483000000 6a00 68???????? 6a0d }
            // n = 7, score = 100
            //   8d8d58ffffff         | lea                 ecx, [ebp - 0xa8]
            //   e8????????           |                     
            //   83f8ff               | cmp                 eax, -1
            //   0f8483000000         | je                  0x89
            //   6a00                 | push                0
            //   68????????           |                     
            //   6a0d                 | push                0xd

        $sequence_5 = { 57 3bf8 7731 8d0439 83fa10 898550ffffff }
            // n = 6, score = 100
            //   57                   | push                edi
            //   3bf8                 | cmp                 edi, eax
            //   7731                 | ja                  0x33
            //   8d0439               | lea                 eax, [ecx + edi]
            //   83fa10               | cmp                 edx, 0x10
            //   898550ffffff         | mov                 dword ptr [ebp - 0xb0], eax

        $sequence_6 = { 51 50 e8???????? 837de408 8d45d0 ffb518ffffff }
            // n = 6, score = 100
            //   51                   | push                ecx
            //   50                   | push                eax
            //   e8????????           |                     
            //   837de408             | cmp                 dword ptr [ebp - 0x1c], 8
            //   8d45d0               | lea                 eax, [ebp - 0x30]
            //   ffb518ffffff         | push                dword ptr [ebp - 0xe8]

        $sequence_7 = { 50 e8???????? 83c40c c78580f7ffff00000000 33c0 c78584f7ffff07000000 8d8db0f7ffff }
            // n = 7, score = 100
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   c78580f7ffff00000000     | mov    dword ptr [ebp - 0x880], 0
            //   33c0                 | xor                 eax, eax
            //   c78584f7ffff07000000     | mov    dword ptr [ebp - 0x87c], 7
            //   8d8db0f7ffff         | lea                 ecx, [ebp - 0x850]

        $sequence_8 = { 33c9 66890c46 8b35???????? 53 ffd6 57 }
            // n = 6, score = 100
            //   33c9                 | xor                 ecx, ecx
            //   66890c46             | mov                 word ptr [esi + eax*2], cx
            //   8b35????????         |                     
            //   53                   | push                ebx
            //   ffd6                 | call                esi
            //   57                   | push                edi

        $sequence_9 = { 7810 3de4000000 7309 8b04c5c8220210 5d c3 33c0 }
            // n = 7, score = 100
            //   7810                 | js                  0x12
            //   3de4000000           | cmp                 eax, 0xe4
            //   7309                 | jae                 0xb
            //   8b04c5c8220210       | mov                 eax, dword ptr [eax*8 + 0x100222c8]
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   33c0                 | xor                 eax, eax

    condition:
        7 of them and filesize < 750592
}
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