rule win_computrace_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.computrace."
        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.computrace"
        malpedia_rule_date = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 66895e1a 6a7e 56 e8???????? 8b7d10 895df8 }
            // n = 6, score = 200
            //   66895e1a             | mov                 word ptr [esi + 0x1a], bx
            //   6a7e                 | push                0x7e
            //   56                   | push                esi
            //   e8????????           |                     
            //   8b7d10               | mov                 edi, dword ptr [ebp + 0x10]
            //   895df8               | mov                 dword ptr [ebp - 8], ebx

        $sequence_1 = { 50 8b1d???????? ffd3 c745e428000000 6a00 }
            // n = 5, score = 200
            //   50                   | push                eax
            //   8b1d????????         |                     
            //   ffd3                 | call                ebx
            //   c745e428000000       | mov                 dword ptr [ebp - 0x1c], 0x28
            //   6a00                 | push                0

        $sequence_2 = { 85c0 755b a1???????? 56 897028 e8???????? }
            // n = 6, score = 200
            //   85c0                 | test                eax, eax
            //   755b                 | jne                 0x5d
            //   a1????????           |                     
            //   56                   | push                esi
            //   897028               | mov                 dword ptr [eax + 0x28], esi
            //   e8????????           |                     

        $sequence_3 = { 56 6888130000 6a02 5b 53 892d???????? e8???????? }
            // n = 7, score = 200
            //   56                   | push                esi
            //   6888130000           | push                0x1388
            //   6a02                 | push                2
            //   5b                   | pop                 ebx
            //   53                   | push                ebx
            //   892d????????         |                     
            //   e8????????           |                     

        $sequence_4 = { 7442 6af6 ffd3 3945e0 7539 c745d801000000 808ebc1b000004 }
            // n = 7, score = 200
            //   7442                 | je                  0x44
            //   6af6                 | push                -0xa
            //   ffd3                 | call                ebx
            //   3945e0               | cmp                 dword ptr [ebp - 0x20], eax
            //   7539                 | jne                 0x3b
            //   c745d801000000       | mov                 dword ptr [ebp - 0x28], 1
            //   808ebc1b000004       | or                  byte ptr [esi + 0x1bbc], 4

        $sequence_5 = { a1???????? 8b483c 03c8 8bd1 2bd0 83c216 33c0 }
            // n = 7, score = 200
            //   a1????????           |                     
            //   8b483c               | mov                 ecx, dword ptr [eax + 0x3c]
            //   03c8                 | add                 ecx, eax
            //   8bd1                 | mov                 edx, ecx
            //   2bd0                 | sub                 edx, eax
            //   83c216               | add                 edx, 0x16
            //   33c0                 | xor                 eax, eax

        $sequence_6 = { 57 e8???????? 8b4608 85c0 7424 83783000 741e }
            // n = 7, score = 200
            //   57                   | push                edi
            //   e8????????           |                     
            //   8b4608               | mov                 eax, dword ptr [esi + 8]
            //   85c0                 | test                eax, eax
            //   7424                 | je                  0x26
            //   83783000             | cmp                 dword ptr [eax + 0x30], 0
            //   741e                 | je                  0x20

        $sequence_7 = { 6a1e e8???????? 8020db a1???????? 83c022 a3???????? }
            // n = 6, score = 200
            //   6a1e                 | push                0x1e
            //   e8????????           |                     
            //   8020db               | and                 byte ptr [eax], 0xdb
            //   a1????????           |                     
            //   83c022               | add                 eax, 0x22
            //   a3????????           |                     

        $sequence_8 = { ff15???????? 68???????? 8bf8 e8???????? 8d4df8 51 }
            // n = 6, score = 200
            //   ff15????????         |                     
            //   68????????           |                     
            //   8bf8                 | mov                 edi, eax
            //   e8????????           |                     
            //   8d4df8               | lea                 ecx, [ebp - 8]
            //   51                   | push                ecx

        $sequence_9 = { 8b750c 8b7d10 8b1f 837d0c00 750b 8b35???????? bb05000000 }
            // n = 7, score = 200
            //   8b750c               | mov                 esi, dword ptr [ebp + 0xc]
            //   8b7d10               | mov                 edi, dword ptr [ebp + 0x10]
            //   8b1f                 | mov                 ebx, dword ptr [edi]
            //   837d0c00             | cmp                 dword ptr [ebp + 0xc], 0
            //   750b                 | jne                 0xd
            //   8b35????????         |                     
            //   bb05000000           | mov                 ebx, 5

    condition:
        7 of them and filesize < 73728
}

rule win_computrace_w0 {
    meta:
        author = "ASERT"
        description = "Absolute Computrace Agent Executable"
        reference = "https://asert.arbornetworks.com/lojack-becomes-a-double-agent/#Yara"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.computrace"
        malpedia_version = "20180503"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""

    strings:
        $a = { D1 E0 F5 8B 4D 0C 83 D1 00 8B EC FF 33 83 C3 04 }
        $b1 = { 72 70 63 6E 65 74 70 2E 65 78 65 00 72 70 63 6E 65 74 70 00 }
        $b2 = { 54 61 67 49 64 00 }
    condition:
        $a or ($b1 and $b2)
}