{"group":"medusalocker","count":1,"rules":[{"rule_name":"medusalocker.yar","rule_text":"rule win_medusalocker_auto {\n\n    meta:\n        author = \"Felix Bilstein - yara-signator at cocacoding dot com\"\n        date = \"2023-07-11\"\n        version = \"1\"\n        description = \"Detects win.medusalocker.\"\n        info = \"autogenerated rule brought to you by yara-signator\"\n        tool = \"yara-signator v0.6.0\"\n        signator_config = \"callsandjumps;datarefs;binvalue\"\n        malpedia_reference = \"https://malpedia.caad.fkie.fraunhofer.de/details/win.medusalocker\"\n        malpedia_rule_date = \"20230705\"\n        malpedia_hash = \"42d0574f4405bd7d2b154d321d345acb18834a41\"\n        malpedia_version = \"20230715\"\n        malpedia_license = \"CC BY-SA 4.0\"\n        malpedia_sharing = \"TLP:WHITE\"\n\n    /* DISCLAIMER\n     * The strings used in this rule have been automatically selected from the\n     * disassembly of memory dumps and unpacked files, using YARA-Signator.\n     * The code and documentation is published here:\n     * https://github.com/fxb-cocacoding/yara-signator\n     * As Malpedia is used as data source, please note that for a given\n     * number of families, only single samples are documented.\n     * This likely impacts the degree of generalization these rules will offer.\n     * Take the described generation method also into consideration when you\n     * apply the rules in your use cases and assign them confidence levels.\n     */\n\n\n    strings:\n        $sequence_0 = { 8b45fc 83781000 7419 8b4dfc 8b5110 }\n            // n = 5, score = 400\n            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]\n            //   83781000             | cmp                 dword ptr [eax + 0x10], 0\n            //   7419                 | je                  0x1b\n            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]\n            //   8b5110               | mov                 edx, dword ptr [ecx + 0x10]\n\n        $sequence_1 = { e8???????? 8b08 51 8d95f4fdffff 52 e8???????? 83c40c }\n            // n = 7, score = 400\n            //   e8????????           |                     \n            //   8b08                 | mov                 ecx, dword ptr [eax]\n            //   51                   | push                ecx\n            //   8d95f4fdffff         | lea                 edx, [ebp - 0x20c]\n            //   52                   | push                edx\n            //   e8????????           |                     \n            //   83c40c               | add                 esp, 0xc\n\n        $sequence_2 = { 8b45e4 50 8b4dec 83c104 e8???????? 8bc8 e8???????? }\n            // n = 7, score = 400\n            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]\n            //   50                   | push                eax\n            //   8b4dec               | mov                 ecx, dword ptr [ebp - 0x14]\n            //   83c104               | add                 ecx, 4\n            //   e8????????           |                     \n            //   8bc8                 | mov                 ecx, eax\n            //   e8????????           |                     \n\n        $sequence_3 = { 83c108 51 e8???????? 83c408 8945d0 837dd003 744d }\n            // n = 7, score = 400\n            //   83c108               | add                 ecx, 8\n            //   51                   | push                ecx\n            //   e8????????           |                     \n            //   83c408               | add                 esp, 8\n            //   8945d0               | mov                 dword ptr [ebp - 0x30], eax\n            //   837dd003             | cmp                 dword ptr [ebp - 0x30], 3\n            //   744d                 | je                  0x4f\n\n        $sequence_4 = { e8???????? 83c42c 8945e8 8b4df8 e8???????? 8845ff 0fb655ff }\n            // n = 7, score = 400\n            //   e8????????           |                     \n            //   83c42c               | add                 esp, 0x2c\n            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax\n            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]\n            //   e8????????           |                     \n            //   8845ff               | mov                 byte ptr [ebp - 1], al\n            //   0fb655ff             | movzx               edx, byte ptr [ebp - 1]\n\n        $sequence_5 = { eb11 6a01 8d4de8 e8???????? 8bc8 e8???????? }\n            // n = 6, score = 400\n            //   eb11                 | jmp                 0x13\n            //   6a01                 | push                1\n            //   8d4de8               | lea                 ecx, [ebp - 0x18]\n            //   e8????????           |                     \n            //   8bc8                 | mov                 ecx, eax\n            //   e8????????           |                     \n\n        $sequence_6 = { 83c408 8be5 5d c20c00 55 8bec 51 }\n            // n = 7, score = 400\n            //   83c408               | add                 esp, 8\n            //   8be5                 | mov                 esp, ebp\n            //   5d                   | pop                 ebp\n            //   c20c00               | ret                 0xc\n            //   55                   | push                ebp\n            //   8bec                 | mov                 ebp, esp\n            //   51                   | push                ecx\n\n        $sequence_7 = { e8???????? 83c018 8bc8 e8???????? 85c0 753e 8b4dec }\n            // n = 7, score = 400\n            //   e8????????           |                     \n            //   83c018               | add                 eax, 0x18\n            //   8bc8                 | mov                 ecx, eax\n            //   e8????????           |                     \n            //   85c0                 | test                eax, eax\n            //   753e                 | jne                 0x40\n            //   8b4dec               | mov                 ecx, dword ptr [ebp - 0x14]\n\n        $sequence_8 = { 8b450c 50 e8???????? 83c404 8945f8 837df800 741c }\n            // n = 7, score = 400\n            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]\n            //   50                   | push                eax\n            //   e8????????           |                     \n            //   83c404               | add                 esp, 4\n            //   8945f8               | mov                 dword ptr [ebp - 8], eax\n            //   837df800             | cmp                 dword ptr [ebp - 8], 0\n            //   741c                 | je                  0x1e\n\n        $sequence_9 = { 8d45f4 64a300000000 894dbc 33c0 }\n            // n = 4, score = 400\n            //   8d45f4               | lea                 eax, [ebp - 0xc]\n            //   64a300000000         | mov                 dword ptr fs:[0], eax\n            //   894dbc               | mov                 dword ptr [ebp - 0x44], ecx\n            //   33c0                 | xor                 eax, eax\n\n    condition:\n        7 of them and filesize < 1433600\n}","sha256":"b1055704c58a6c62aad98ceadcace8800ca7f2497cab9570257576c912bab17d","byte_size":7081,"updated_at":"2026-06-24 05:16:03"}]}