SYMBOLCOMMON_NAMEaka. SYNONYMS
win.dexter (Back to overview)

Dexter

aka: LusyPOS
VTCollection    

Dexter is a computer virus or point of sale malware which infects computers running Microsoft Windows and was discovered by IT security firm Seculert, in December 2012. It infects PoS systems worldwide and steals sensitive information such as Credit Card and Debit Card information.

References
2012-12-23Contagio DumpMila Parkour
Dec 2012 Dexter - POS Infostealer samples and information
Dexter
2012-12-21Trend MicroJason Pantig
Infostealer Dexter Targets Checkout Systems
Dexter
2012-12-12Volatility LabsMichael Hale Ligh
Unpacking Dexter POS "Memory Dump Parsing" Malware
Dexter
Yara Rules
[TLP:WHITE] win_dexter_auto (20251219 | Detects win.dexter.)
rule win_dexter_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-01-05"
        version = "1"
        description = "Detects win.dexter."
        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.dexter"
        malpedia_rule_date = "20260105"
        malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79"
        malpedia_version = "20251219"
        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 = { 6a59 ff15???????? 85c0 7414 68???????? 8b4d08 }
            // n = 6, score = 400
            //   6a59                 | push                0x59
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7414                 | je                  0x16
            //   68????????           |                     
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]

        $sequence_1 = { 50 6a00 ff15???????? 68???????? 68???????? }
            // n = 5, score = 400
            //   50                   | push                eax
            //   6a00                 | push                0
            //   ff15????????         |                     
            //   68????????           |                     
            //   68????????           |                     

        $sequence_2 = { 8b0d???????? 51 ff15???????? 8b15???????? 8955fc 8b45fc 50 }
            // n = 7, score = 400
            //   8b0d????????         |                     
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   8b15????????         |                     
            //   8955fc               | mov                 dword ptr [ebp - 4], edx
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   50                   | push                eax

        $sequence_3 = { 8b45fc 50 ff15???????? 8b0d???????? 51 ff15???????? ebc6 }
            // n = 7, score = 400
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b0d????????         |                     
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   ebc6                 | jmp                 0xffffffc8

        $sequence_4 = { 83c40c 68???????? ff15???????? 6a00 6a00 6a00 6a00 }
            // n = 7, score = 400
            //   83c40c               | add                 esp, 0xc
            //   68????????           |                     
            //   ff15????????         |                     
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a00                 | push                0

        $sequence_5 = { e9???????? 6a59 ff15???????? 85c0 7514 68???????? 8b4d08 }
            // n = 7, score = 400
            //   e9????????           |                     
            //   6a59                 | push                0x59
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7514                 | jne                 0x16
            //   68????????           |                     
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]

        $sequence_6 = { e8???????? 83c410 8b4508 50 8b4d10 }
            // n = 5, score = 400
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   50                   | push                eax
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]

        $sequence_7 = { ff15???????? 6a4a 6a00 68???????? e8???????? 83c40c 6a4a }
            // n = 7, score = 400
            //   ff15????????         |                     
            //   6a4a                 | push                0x4a
            //   6a00                 | push                0
            //   68????????           |                     
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   6a4a                 | push                0x4a

        $sequence_8 = { 7514 68???????? 8b5508 52 ff15???????? e9???????? }
            // n = 6, score = 400
            //   7514                 | jne                 0x16
            //   68????????           |                     
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   52                   | push                edx
            //   ff15????????         |                     
            //   e9????????           |                     

        $sequence_9 = { 51 6a08 8b15???????? 52 ff15???????? 8945f8 }
            // n = 6, score = 400
            //   51                   | push                ecx
            //   6a08                 | push                8
            //   8b15????????         |                     
            //   52                   | push                edx
            //   ff15????????         |                     
            //   8945f8               | mov                 dword ptr [ebp - 8], eax

    condition:
        7 of them and filesize < 98304
}
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