SYMBOLCOMMON_NAMEaka. SYNONYMS
win.sfile (Back to overview)

Sfile

aka: Morseop, Escal

Ransomware

References
2022-06-06SentinelOneNiranjan Jayanand
@online{jayanand:20220606:from:0fa017a, author = {Niranjan Jayanand}, title = {{From the Front Lines | Another Rebrand? Mindware and SFile Ransomware Technical Breakdown}}, date = {2022-06-06}, organization = {SentinelOne}, url = {https://www.sentinelone.com/blog/from-the-front-lines-another-rebrand-mindware-and-sfile-ransomware-technical-breakdown/}, language = {English}, urldate = {2022-06-09} } From the Front Lines | Another Rebrand? Mindware and SFile Ransomware Technical Breakdown
Mindware Sfile
2020-08-21Twitter (@GrujaRS)GrujaRS
@online{grujars:20200821:new:2433327, author = {GrujaRS}, title = {{New #Morseop #Ransomware}}, date = {2020-08-21}, organization = {Twitter (@GrujaRS)}, url = {https://twitter.com/GrujaRS/status/1296856836944076802?s=20}, language = {English}, urldate = {2021-12-17} } New #Morseop #Ransomware
Sfile
2020-02-06ID RansomwareAndrew Ivanov
@online{ivanov:20200206:sfile:d731e7d, author = {Andrew Ivanov}, title = {{Sfile Ransomware}}, date = {2020-02-06}, organization = {ID Ransomware}, url = {https://id-ransomware.blogspot.com/2020/02/sfile2-ransomware.html}, language = {Russian}, urldate = {2021-12-17} } Sfile Ransomware
Sfile
Yara Rules
[TLP:WHITE] win_sfile_auto (20230715 | Detects win.sfile.)
rule win_sfile_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.sfile."
        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.sfile"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { c745e800000000 8b45e4 50 ff15???????? }
            // n = 4, score = 300
            //   c745e800000000       | mov                 dword ptr [ebp - 0x18], 0
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   50                   | push                eax
            //   ff15????????         |                     

        $sequence_1 = { 8b485c 51 8b55fc 8b4204 }
            // n = 4, score = 300
            //   8b485c               | mov                 ecx, dword ptr [eax + 0x5c]
            //   51                   | push                ecx
            //   8b55fc               | mov                 edx, dword ptr [ebp - 4]
            //   8b4204               | mov                 eax, dword ptr [edx + 4]

        $sequence_2 = { 740d 8b55f8 8b4258 50 ff15???????? 8b4df8 8b5134 }
            // n = 7, score = 300
            //   740d                 | je                  0xf
            //   8b55f8               | mov                 edx, dword ptr [ebp - 8]
            //   8b4258               | mov                 eax, dword ptr [edx + 0x58]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   8b5134               | mov                 edx, dword ptr [ecx + 0x34]

        $sequence_3 = { 7433 6aff 8b4dfc 8b5118 52 }
            // n = 5, score = 300
            //   7433                 | je                  0x35
            //   6aff                 | push                -1
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   8b5118               | mov                 edx, dword ptr [ecx + 0x18]
            //   52                   | push                edx

        $sequence_4 = { 894140 8b55f8 8b828c050000 50 e8???????? 8b4df8 51 }
            // n = 7, score = 300
            //   894140               | mov                 dword ptr [ecx + 0x40], eax
            //   8b55f8               | mov                 edx, dword ptr [ebp - 8]
            //   8b828c050000         | mov                 eax, dword ptr [edx + 0x58c]
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   51                   | push                ecx

        $sequence_5 = { 83f810 7309 c745f410000000 eb10 8b4df8 8d148d10000000 }
            // n = 6, score = 300
            //   83f810               | cmp                 eax, 0x10
            //   7309                 | jae                 0xb
            //   c745f410000000       | mov                 dword ptr [ebp - 0xc], 0x10
            //   eb10                 | jmp                 0x12
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   8d148d10000000       | lea                 edx, [ecx*4 + 0x10]

        $sequence_6 = { 7527 6a10 8b5510 52 }
            // n = 4, score = 300
            //   7527                 | jne                 0x29
            //   6a10                 | push                0x10
            //   8b5510               | mov                 edx, dword ptr [ebp + 0x10]
            //   52                   | push                edx

        $sequence_7 = { 51 e8???????? 83c408 eb13 8d95e4fdffff }
            // n = 5, score = 300
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   eb13                 | jmp                 0x15
            //   8d95e4fdffff         | lea                 edx, [ebp - 0x21c]

        $sequence_8 = { 8b45e8 8b4df8 8b511c 8910 }
            // n = 4, score = 300
            //   8b45e8               | mov                 eax, dword ptr [ebp - 0x18]
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   8b511c               | mov                 edx, dword ptr [ecx + 0x1c]
            //   8910                 | mov                 dword ptr [eax], edx

        $sequence_9 = { ff15???????? 8b55f0 52 ff15???????? 8b45ec }
            // n = 5, score = 300
            //   ff15????????         |                     
            //   8b55f0               | mov                 edx, dword ptr [ebp - 0x10]
            //   52                   | push                edx
            //   ff15????????         |                     
            //   8b45ec               | mov                 eax, dword ptr [ebp - 0x14]

    condition:
        7 of them and filesize < 588800
}
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