SYMBOLCOMMON_NAMEaka. SYNONYMS
win.screencap (Back to overview)

ScreenCap


SentinelOne describes this malware as capable of doing screen capture and keylogging. It is uses by a threat cluster they named WIP19, targeting telecommunications and IT service providers in the Middle East and Asia.

References
2022-10-12SentinelOneJoey Chen, Amitai Ben Shushan Ehrlich
@online{chen:20221012:wip19:672e865, author = {Joey Chen and Amitai Ben Shushan Ehrlich}, title = {{WIP19 Espionage | New Chinese APT Targets IT Service Providers and Telcos With Signed Malware}}, date = {2022-10-12}, organization = {SentinelOne}, url = {https://www.sentinelone.com/labs/wip19-espionage-new-chinese-apt-targets-it-service-providers-and-telcos-with-signed-malware/}, language = {English}, urldate = {2022-10-24} } WIP19 Espionage | New Chinese APT Targets IT Service Providers and Telcos With Signed Malware
Maggie ScreenCap
Yara Rules
[TLP:WHITE] win_screencap_auto (20230125 | Detects win.screencap.)
rule win_screencap_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.screencap."
        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.screencap"
        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 = { 85c0 7503 57 ebe5 6824b64900 57 e8???????? }
            // n = 7, score = 100
            //   85c0                 | mov                 ecx, ebx
            //   7503                 | add                 ecx, 0x6ed9eba1
            //   57                   | add                 ecx, dword ptr [esp + 0x2c]
            //   ebe5                 | add                 eax, ecx
            //   6824b64900           | add                 ebp, eax
            //   57                   | mov                 eax, dword ptr [esp + 0x64]
            //   e8????????           |                     

        $sequence_1 = { 014704 894f08 80bf5097000000 53 743e c1ee0c 83e603 }
            // n = 7, score = 100
            //   014704               | push                dword ptr [edi + 4]
            //   894f08               | push                0xe8a
            //   80bf5097000000       | add                 esp, 0xc
            //   53                   | pop                 edi
            //   743e                 | ret                 
            //   c1ee0c               | push                dword ptr [edi + 4]
            //   83e603               | push                0xe9e

        $sequence_2 = { 33c0 88867a570000 83f902 750e 8d8698670000 8bce 50 }
            // n = 7, score = 100
            //   33c0                 | je                  0x23f
            //   88867a570000         | xor                 edx, edx
            //   83f902               | imul                eax, esi, 0x9c0
            //   750e                 | mov                 dword ptr [esp + 0x14], edx
            //   8d8698670000         | mov                 dword ptr [esp + 0x28], eax
            //   8bce                 | lea                 eax, [esp + 0x2c]
            //   50                   | lea                 esp, [esp]

        $sequence_3 = { 85d2 750d 8d7320 f3a5 8b83b4010000 eb0e 8db5b8fcffff }
            // n = 7, score = 100
            //   85d2                 | push                ebp
            //   750d                 | cmp                 ecx, 0xe0
            //   8d7320               | jne                 0x314
            //   f3a5                 | mov                 bl, byte ptr [edx]
            //   8b83b4010000         | mov                 cl, bl
            //   eb0e                 | and                 cl, 0xc0
            //   8db5b8fcffff         | cmp                 cl, 0x80

        $sequence_4 = { e8???????? 85c0 75b3 5d 5b 5f 32c0 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   85c0                 | mov                 dword ptr [ebp - 0x24], 0
            //   75b3                 | neg                 eax
            //   5d                   | mov                 dword ptr [ebp - 0x20], 0
            //   5b                   | lea                 ecx, [ebp - 0x24]
            //   5f                   | mov                 dword ptr [ebp - 0x1c], 0
            //   32c0                 | sbb                 eax, eax

        $sequence_5 = { 6a00 53 57 8d44242c 50 ff15???????? 894604 }
            // n = 7, score = 100
            //   6a00                 | push                eax
            //   53                   | push                edx
            //   57                   | pop                 esi
            //   8d44242c             | pop                 ebp
            //   50                   | pop                 ebx
            //   ff15????????         |                     
            //   894604               | add                 esp, 0xc

        $sequence_6 = { c7422839000000 eb14 c70201000000 c74224ace54700 c7422835000000 8b4c2414 33f6 }
            // n = 7, score = 100
            //   c7422839000000       | add                 ecx, edx
            //   eb14                 | mov                 ecx, 0x10
            //   c70201000000         | sub                 ecx, ebp
            //   c74224ace54700       | shr                 eax, cl
            //   c7422835000000       | add                 eax, dword ptr [ebp*4 + 0x47ea94]
            //   8b4c2414             | movzx               edx, al
            //   33f6                 | movzx               ecx, word ptr [ebx + edx*2 + 0x4e62]

        $sequence_7 = { 3344242c d1c0 894124 8bce 89442418 8bc3 33c2 }
            // n = 7, score = 100
            //   3344242c             | lea                 eax, [ebx + edi]
            //   d1c0                 | jae                 0x6fc
            //   894124               | cmp                 edx, eax
            //   8bce                 | jae                 0x6fc
            //   89442418             | mov                 eax, dword ptr [esi + 0x4b40]
            //   8bc3                 | add                 ecx, eax
            //   33c2                 | add                 dword ptr [ebx], ebp

        $sequence_8 = { 8dac24a4ceffff b85c310000 e8???????? 6aff 68ee134700 64a1000000005083ec7c a1????????33c58985 }
            // n = 7, score = 100
            //   8dac24a4ceffff       | not                 eax
            //   b85c310000           | inc                 eax
            //   e8????????           |                     
            //   6aff                 | and                 eax, 0x3f
            //   68ee134700           | add                 eax, 0x318
            //   64a1000000005083ec7c     | add    eax, edx
            //   a1????????33c58985     |     

        $sequence_9 = { b920000000 2b4c2424 d3e5 896b14 0fb6afcce14700 894b18 85ed }
            // n = 7, score = 100
            //   b920000000           | sub                 eax, 1
            //   2b4c2424             | jne                 0xe88
            //   d3e5                 | mov                 edi, dword ptr [esp + 0x74]
            //   896b14               | lea                 esi, [esp + 0x2d]
            //   0fb6afcce14700       | movzx               ecx, byte ptr [ecx + 0x493b88]
            //   894b18               | xor                 byte ptr [esp + 0x2c], cl
            //   85ed                 | movzx               ecx, byte ptr [esp + 0x29]

    condition:
        7 of them and filesize < 1391616
}
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