SYMBOLCOMMON_NAMEaka. SYNONYMS
win.grease (Back to overview)

GREASE


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References
2018-12-05NetScoutASERT Team
@online{team:20181205:stolen:bc9dd60, author = {ASERT Team}, title = {{STOLEN PENCIL Campaign Targets Academia}}, date = {2018-12-05}, organization = {NetScout}, url = {https://asert.arbornetworks.com/stolen-pencil-campaign-targets-academia/}, language = {English}, urldate = {2020-01-08} } STOLEN PENCIL Campaign Targets Academia
GREASE MECHANICAL
Yara Rules
[TLP:WHITE] win_grease_auto (20201014 | autogenerated rule brought to you by yara-signator)
rule win_grease_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-10-14"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.5.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.grease"
        malpedia_rule_date = "20201014"
        malpedia_hash = "a7e3bd57eaf12bf3ea29a863c041091ba3af9ac9"
        malpedia_version = "20201014"
        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 0f85e7000000 488b4c2460 }
            // n = 4, score = 300
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f85e7000000         | jne                 0x38
            //   488b4c2460           | dec                 eax

        $sequence_1 = { 7534 488b4c2450 488d442458 41b904000000 4533c0 }
            // n = 5, score = 300
            //   7534                 | jne                 0x36
            //   488b4c2450           | dec                 eax
            //   488d442458           | mov                 ecx, dword ptr [esp + 0x50]
            //   41b904000000         | dec                 eax
            //   4533c0               | lea                 eax, [esp + 0x58]

        $sequence_2 = { ff15???????? b801000000 488b8c2480020000 4833cc }
            // n = 4, score = 300
            //   ff15????????         |                     
            //   b801000000           | dec                 eax
            //   488b8c2480020000     | mov                 dword ptr [esp + 0x38], eax
            //   4833cc               | dec                 eax

        $sequence_3 = { 48895c2448 48895c2440 48895c2438 48895c2430 }
            // n = 4, score = 300
            //   48895c2448           | dec                 eax
            //   48895c2440           | xor                 ecx, esp
            //   48895c2438           | jne                 0x36
            //   48895c2430           | dec                 eax

        $sequence_4 = { 41b904000000 4533c0 488bd3 c744242804000000 4889442420 }
            // n = 5, score = 300
            //   41b904000000         | test                eax, eax
            //   4533c0               | jne                 0x40
            //   488bd3               | mov                 eax, 1
            //   c744242804000000     | dec                 eax
            //   4889442420           | mov                 ecx, dword ptr [esp + 0x280]

        $sequence_5 = { 33d2 ff15???????? b9e8030000 ff15???????? }
            // n = 4, score = 300
            //   33d2                 | inc                 ecx
            //   ff15????????         |                     
            //   b9e8030000           | mov                 ecx, 4
            //   ff15????????         |                     

        $sequence_6 = { 4533c9 4533c0 4889442420 ff15???????? 85c0 7537 }
            // n = 6, score = 300
            //   4533c9               | mov                 dword ptr [esp + 0x28], 4
            //   4533c0               | inc                 ebp
            //   4889442420           | xor                 ecx, ecx
            //   ff15????????         |                     
            //   85c0                 | dec                 eax
            //   7537                 | mov                 dword ptr [esp + 0x40], edi

        $sequence_7 = { 4533c9 48897c2440 4889442438 48897c2430 }
            // n = 4, score = 300
            //   4533c9               | dec                 eax
            //   48897c2440           | mov                 ecx, dword ptr [esp + 0x60]
            //   4889442438           | dec                 eax
            //   48897c2430           | lea                 eax, [esp + 0x58]

        $sequence_8 = { 52 50 683f000f00 50 50 }
            // n = 5, score = 200
            //   52                   | push                edx
            //   50                   | push                eax
            //   683f000f00           | push                0xf003f
            //   50                   | push                eax
            //   50                   | push                eax

        $sequence_9 = { 4f 0fb60f 40 80b910fe240000 74e8 8a17 }
            // n = 6, score = 100
            //   4f                   | dec                 edi
            //   0fb60f               | movzx               ecx, byte ptr [edi]
            //   40                   | inc                 eax
            //   80b910fe240000       | cmp                 byte ptr [ecx + 0x24fe10], 0
            //   74e8                 | je                  0xffffffea
            //   8a17                 | mov                 dl, byte ptr [edi]

        $sequence_10 = { c684341402000028 eb44 c684341402000024 eb3a c68434140200005d eb30 }
            // n = 6, score = 100
            //   c684341402000028     | add                 esp, 0x290
            //   eb44                 | dec                 eax
            //   c684341402000024     | mov                 dword ptr [esp + 0x40], edi
            //   eb3a                 | dec                 eax
            //   c68434140200005d     | mov                 dword ptr [esp + 0x38], eax
            //   eb30                 | dec                 eax

        $sequence_11 = { 8d34b580c64000 83c00c 3bc6 7304 3910 75f5 }
            // n = 6, score = 100
            //   8d34b580c64000       | dec                 eax
            //   83c00c               | mov                 dword ptr [esp + 0x30], ebx
            //   3bc6                 | dec                 eax
            //   7304                 | mov                 ecx, dword ptr [esp + 0x60]
            //   3910                 | mov                 eax, 1
            //   75f5                 | dec                 eax

        $sequence_12 = { 6a00 50 c644241400 e8???????? 8b0d???????? 51 }
            // n = 6, score = 100
            //   6a00                 | push                0
            //   50                   | push                eax
            //   c644241400           | mov                 byte ptr [esp + 0x14], 0
            //   e8????????           |                     
            //   8b0d????????         |                     
            //   51                   | push                ecx

        $sequence_13 = { c68434340a000040 eb62 c68434340a00007b eb58 }
            // n = 4, score = 100
            //   c68434340a000040     | mov                 ecx, dword ptr [esp + 0x280]
            //   eb62                 | dec                 eax
            //   c68434340a00007b     | xor                 ecx, esp
            //   eb58                 | dec                 eax

        $sequence_14 = { c6440c0870 e9???????? c6440c0873 e9???????? c6440c0874 }
            // n = 5, score = 100
            //   c6440c0870           | dec                 eax
            //   e9????????           |                     
            //   c6440c0873           | mov                 dword ptr [esp + 0x48], ebx
            //   e9????????           |                     
            //   c6440c0874           | dec                 eax

        $sequence_15 = { e9???????? c68434380b000062 e9???????? c68434380b00006f e9???????? c68434380b00006a e9???????? }
            // n = 7, score = 100
            //   e9????????           |                     
            //   c68434380b000062     | mov                 dword ptr [esp + 0x28], 4
            //   e9????????           |                     
            //   c68434380b00006f     | dec                 eax
            //   e9????????           |                     
            //   c68434380b00006a     | mov                 dword ptr [esp + 0x20], eax
            //   e9????????           |                     

        $sequence_16 = { 8d84242c040000 55 50 ffd6 85c0 7502 ffd7 }
            // n = 7, score = 100
            //   8d84242c040000       | mov                 dword ptr [esp + 0x30], edi
            //   55                   | inc                 ebp
            //   50                   | xor                 eax, eax
            //   ffd6                 | mov                 dword ptr [esp + 0x28], 0xf003f
            //   85c0                 | mov                 dword ptr [esp + 0x20], edi
            //   7502                 | dec                 eax
            //   ffd7                 | mov                 ecx, dword ptr [esp + 0x50]

        $sequence_17 = { c6440c086d e9???????? c6440c0871 e9???????? c6440c0866 e9???????? }
            // n = 6, score = 100
            //   c6440c086d           | mov                 dword ptr [esp + 0x40], ebx
            //   e9????????           |                     
            //   c6440c0871           | dec                 eax
            //   e9????????           |                     
            //   c6440c0866           | mov                 dword ptr [esp + 0x38], ebx
            //   e9????????           |                     

        $sequence_18 = { a1???????? 33c4 8984242c0b0000 56 8bb424380b0000 }
            // n = 5, score = 100
            //   a1????????           |                     
            //   33c4                 | xor                 eax, esp
            //   8984242c0b0000       | mov                 dword ptr [esp + 0xb2c], eax
            //   56                   | push                esi
            //   8bb424380b0000       | mov                 esi, dword ptr [esp + 0xb38]

        $sequence_19 = { eb06 8b35???????? 8d542424 68???????? 52 e8???????? }
            // n = 6, score = 100
            //   eb06                 | jmp                 8
            //   8b35????????         |                     
            //   8d542424             | lea                 edx, [esp + 0x24]
            //   68????????           |                     
            //   52                   | push                edx
            //   e8????????           |                     

        $sequence_20 = { 8d4c2430 51 6802000080 c744242804000000 ff15???????? 85c0 7540 }
            // n = 7, score = 100
            //   8d4c2430             | lea                 ecx, [esp + 0x30]
            //   51                   | push                ecx
            //   6802000080           | push                0x80000002
            //   c744242804000000     | mov                 dword ptr [esp + 0x28], 4
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7540                 | jne                 0x42

        $sequence_21 = { 66899c2446010000 66c784244a0100000700 66899c244c010000 66c784244e0100005d00 ffd7 }
            // n = 5, score = 100
            //   66899c2446010000     | mov                 word ptr [esp + 0x146], bx
            //   66c784244a0100000700     | mov    word ptr [esp + 0x14a], 7
            //   66899c244c010000     | mov                 word ptr [esp + 0x14c], bx
            //   66c784244e0100005d00     | mov    word ptr [esp + 0x14e], 0x5d
            //   ffd7                 | call                edi

        $sequence_22 = { 56 ff15???????? 8d542424 68???????? }
            // n = 4, score = 100
            //   56                   | push                esi
            //   ff15????????         |                     
            //   8d542424             | lea                 edx, [esp + 0x24]
            //   68????????           |                     

    condition:
        7 of them and filesize < 278528
}
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