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 (20220808 | Detects win.sfile.)
rule win_sfile_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        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 = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 8b4008 8b0c90 894dfc 8b5508 8b4220 83c001 }
            // n = 6, score = 300
            //   8b4008               | mov                 eax, dword ptr [eax + 8]
            //   8b0c90               | mov                 ecx, dword ptr [eax + edx*4]
            //   894dfc               | mov                 dword ptr [ebp - 4], ecx
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   8b4220               | mov                 eax, dword ptr [edx + 0x20]
            //   83c001               | add                 eax, 1

        $sequence_1 = { c745f800000000 ff15???????? 8945fc 8b4508 8b480c 51 8b5508 }
            // n = 7, score = 300
            //   c745f800000000       | mov                 dword ptr [ebp - 8], 0
            //   ff15????????         |                     
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8b480c               | mov                 ecx, dword ptr [eax + 0xc]
            //   51                   | push                ecx
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]

        $sequence_2 = { 56 57 8b4508 8b4810 }
            // n = 4, score = 300
            //   56                   | push                esi
            //   57                   | push                edi
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8b4810               | mov                 ecx, dword ptr [eax + 0x10]

        $sequence_3 = { 83c2fe 8955f0 8b45f0 668b4802 }
            // n = 4, score = 300
            //   83c2fe               | add                 edx, -2
            //   8955f0               | mov                 dword ptr [ebp - 0x10], edx
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   668b4802             | mov                 cx, word ptr [eax + 2]

        $sequence_4 = { 8945fc 8b4d08 8b5108 8b410c 8b4dfc 895108 89410c }
            // n = 7, score = 300
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   8b5108               | mov                 edx, dword ptr [ecx + 8]
            //   8b410c               | mov                 eax, dword ptr [ecx + 0xc]
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   895108               | mov                 dword ptr [ecx + 8], edx
            //   89410c               | mov                 dword ptr [ecx + 0xc], eax

        $sequence_5 = { e8???????? 8945ec 837dec00 746e }
            // n = 4, score = 300
            //   e8????????           |                     
            //   8945ec               | mov                 dword ptr [ebp - 0x14], eax
            //   837dec00             | cmp                 dword ptr [ebp - 0x14], 0
            //   746e                 | je                  0x70

        $sequence_6 = { 68fc000000 8b4df0 8b11 52 }
            // n = 4, score = 300
            //   68fc000000           | push                0xfc
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]
            //   8b11                 | mov                 edx, dword ptr [ecx]
            //   52                   | push                edx

        $sequence_7 = { 8b4df8 8b10 8b4914 8b4204 ffd0 }
            // n = 5, score = 300
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   8b10                 | mov                 edx, dword ptr [eax]
            //   8b4914               | mov                 ecx, dword ptr [ecx + 0x14]
            //   8b4204               | mov                 eax, dword ptr [edx + 4]
            //   ffd0                 | call                eax

        $sequence_8 = { 8b751c 8b4d20 f3a4 837d0802 }
            // n = 4, score = 300
            //   8b751c               | mov                 esi, dword ptr [ebp + 0x1c]
            //   8b4d20               | mov                 ecx, dword ptr [ebp + 0x20]
            //   f3a4                 | rep movsb           byte ptr es:[edi], byte ptr [esi]
            //   837d0802             | cmp                 dword ptr [ebp + 8], 2

        $sequence_9 = { 8b4df8 c7413400000000 8b55f8 c7423800000000 8b45f8 c7402c00000000 8b4df8 }
            // n = 7, score = 300
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   c7413400000000       | mov                 dword ptr [ecx + 0x34], 0
            //   8b55f8               | mov                 edx, dword ptr [ebp - 8]
            //   c7423800000000       | mov                 dword ptr [edx + 0x38], 0
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]
            //   c7402c00000000       | mov                 dword ptr [eax + 0x2c], 0
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]

    condition:
        7 of them and filesize < 588800
}
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