SYMBOLCOMMON_NAMEaka. SYNONYMS
win.lazarloader (Back to overview)

LazarLoader

Actor(s): Lazarus Group

VTCollection    

There is no description at this point.

References
2023-06-08AhnLabASEC Analysis Team
Lazarus Group exploiting vulnerabilities in domestic financial security solutions
LazarDoor LazarLoader
2022-12-27KasperskySeongsu Park
BlueNoroff introduces new methods bypassing MoTW
LazarLoader Unidentified 101 (Lazarus?)
Yara Rules
[TLP:WHITE] win_lazarloader_auto (20260504 | Detects win.lazarloader.)
rule win_lazarloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.lazarloader."
        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.lazarloader"
        malpedia_rule_date = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { 48894de8 488945f0 488d15a0bd0000 b805000000 894520 894528 }
            // n = 6, score = 100
            //   48894de8             | dec                 eax
            //   488945f0             | test                ebx, ebx
            //   488d15a0bd0000       | jne                 0x34e
            //   b805000000           | dec                 eax
            //   894520               | mov                 eax, edi
            //   894528               | dec                 ecx

        $sequence_1 = { 488bd7 4c8d05fecd0000 83e23f 488bcf }
            // n = 4, score = 100
            //   488bd7               | dec                 eax
            //   4c8d05fecd0000       | cmp                 ecx, eax
            //   83e23f               | dec                 eax
            //   488bcf               | test                ecx, ecx

        $sequence_2 = { 33c0 b906020000 f3aa 33c0 66898424d0060000 488d8424d2060000 488bf8 }
            // n = 7, score = 100
            //   33c0                 | js                  0x835
            //   b906020000           | jae                 0x82f
            //   f3aa                 | dec                 eax
            //   33c0                 | mov                 edi, ebx
            //   66898424d0060000     | dec                 esp
            //   488d8424d2060000     | lea                 esi, [0x12422]
            //   488bf8               | test                ebx, ebx

        $sequence_3 = { 488bc2 e9???????? 493bec 0f84be000000 8b7500 33c0 f04d0fb1bcf120ba0100 }
            // n = 7, score = 100
            //   488bc2               | imul                ecx, ecx, 0
            //   e9????????           |                     
            //   493bec               | dec                 eax
            //   0f84be000000         | mov                 edx, dword ptr [esp + 0x58]
            //   8b7500               | movsx               ecx, byte ptr [edx + ecx]
            //   33c0                 | dec                 eax
            //   f04d0fb1bcf120ba0100     | arpl    word ptr [esp + 0x44], cx

        $sequence_4 = { 4889842490000000 488b442470 0fb700 6689442432 488b442458 0fb74c2432 }
            // n = 6, score = 100
            //   4889842490000000     | cmova               ebp, eax
            //   488b442470           | inc                 esp
            //   0fb700               | mov                 dword ptr [esp + 0x48], ebp
            //   6689442432           | inc                 ecx
            //   488b442458           | lea                 eax, [ebp - 1]
            //   0fb74c2432           | movzx               ecx, byte ptr [edx + eax*4 + 0x13fd2]

        $sequence_5 = { 4885c9 7430 53 4883ec20 488d0563810000 }
            // n = 5, score = 100
            //   4885c9               | movzx               esi, byte ptr [edx + eax*4 + 0x13fd3]
            //   7430                 | mov                 ebx, ecx
            //   53                   | mov                 edi, eax
            //   4883ec20             | xor                 edx, edx
            //   488d0563810000       | dec                 eax

        $sequence_6 = { eb19 488d1dec1e0100 eb10 488d1df31e0100 eb07 488d1dd21e0100 }
            // n = 6, score = 100
            //   eb19                 | jmp                 0x77
            //   488d1dec1e0100       | dec                 eax
            //   eb10                 | mov                 eax, ebx
            //   488d1df31e0100       | dec                 ecx
            //   eb07                 | xchg                dword ptr [edi + esi*8 + 0x1c0d0], eax
            //   488d1dd21e0100       | jne                 0x73

        $sequence_7 = { 4883ec20 e8???????? 488b05???????? 488d1da7710100 }
            // n = 4, score = 100
            //   4883ec20             | dec                 eax
            //   e8????????           |                     
            //   488b05????????       |                     
            //   488d1da7710100       | lea                 edx, [0xffffe52d]

        $sequence_8 = { e8???????? 89442460 33c9 e8???????? }
            // n = 4, score = 100
            //   e8????????           |                     
            //   89442460             | dec                 eax
            //   33c9                 | lea                 eax, [0x14767]
            //   e8????????           |                     

        $sequence_9 = { 85c0 750d 488bcb e8???????? e9???????? 4c8d2557230100 }
            // n = 6, score = 100
            //   85c0                 | lea                 ecx, [ebx + ebx*4]
            //   750d                 | dec                 eax
            //   488bcb               | lea                 ecx, [eax + ecx*8]
            //   e8????????           |                     
            //   e9????????           |                     
            //   4c8d2557230100       | dec                 eax

    condition:
        7 of them and filesize < 364544
}
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