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 (20230125 | Detects win.sfile.)
rule win_sfile_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        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 = "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 = { c705????????00000000 833d????????00 7534 6850010000 6a40 }
            // n = 5, score = 300
            //   c705????????00000000     |     
            //   833d????????00       |                     
            //   7534                 | jne                 0x36
            //   6850010000           | push                0x150
            //   6a40                 | push                0x40

        $sequence_1 = { 55 8bec 837d1000 7654 e8???????? 0fb6c0 }
            // n = 6, score = 300
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   837d1000             | cmp                 dword ptr [ebp + 0x10], 0
            //   7654                 | jbe                 0x56
            //   e8????????           |                     
            //   0fb6c0               | movzx               eax, al

        $sequence_2 = { 3945f4 7d89 8b4dfc 034df4 c60100 837dec00 7547 }
            // n = 7, score = 300
            //   3945f4               | cmp                 dword ptr [ebp - 0xc], eax
            //   7d89                 | jge                 0xffffff8b
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   034df4               | add                 ecx, dword ptr [ebp - 0xc]
            //   c60100               | mov                 byte ptr [ecx], 0
            //   837dec00             | cmp                 dword ptr [ebp - 0x14], 0
            //   7547                 | jne                 0x49

        $sequence_3 = { 742d 6a00 8d55f8 52 6800010000 8b4518 }
            // n = 6, score = 300
            //   742d                 | je                  0x2f
            //   6a00                 | push                0
            //   8d55f8               | lea                 edx, [ebp - 8]
            //   52                   | push                edx
            //   6800010000           | push                0x100
            //   8b4518               | mov                 eax, dword ptr [ebp + 0x18]

        $sequence_4 = { e8???????? 8945dc eb07 c745dc00000000 8b55f8 8b45dc }
            // n = 6, score = 300
            //   e8????????           |                     
            //   8945dc               | mov                 dword ptr [ebp - 0x24], eax
            //   eb07                 | jmp                 9
            //   c745dc00000000       | mov                 dword ptr [ebp - 0x24], 0
            //   8b55f8               | mov                 edx, dword ptr [ebp - 8]
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]

        $sequence_5 = { 8b5508 8b4220 83c001 8b4d08 894120 837dfc00 743a }
            // n = 7, score = 300
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   8b4220               | mov                 eax, dword ptr [edx + 0x20]
            //   83c001               | add                 eax, 1
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   894120               | mov                 dword ptr [ecx + 0x20], eax
            //   837dfc00             | cmp                 dword ptr [ebp - 4], 0
            //   743a                 | je                  0x3c

        $sequence_6 = { 8d95e4fdffff 52 8b4514 50 e8???????? 83c408 eb49 }
            // n = 7, score = 300
            //   8d95e4fdffff         | lea                 edx, [ebp - 0x21c]
            //   52                   | push                edx
            //   8b4514               | mov                 eax, dword ptr [ebp + 0x14]
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   eb49                 | jmp                 0x4b

        $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 = { b001 eb08 ebd5 32c0 eb02 b001 }
            // n = 6, score = 300
            //   b001                 | mov                 al, 1
            //   eb08                 | jmp                 0xa
            //   ebd5                 | jmp                 0xffffffd7
            //   32c0                 | xor                 al, al
            //   eb02                 | jmp                 4
            //   b001                 | mov                 al, 1

        $sequence_9 = { 8955f4 8b45f4 50 6a40 }
            // n = 4, score = 300
            //   8955f4               | mov                 dword ptr [ebp - 0xc], edx
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   50                   | push                eax
            //   6a40                 | push                0x40

    condition:
        7 of them and filesize < 588800
}
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