SYMBOLCOMMON_NAMEaka. SYNONYMS
win.buer (Back to overview)

Buer

aka: Buerloader, RustyBuer

Buer is a downloader sold on underground forums and used by threat actors to deliver payload malware onto target machines. It has been observed in email campaigns and has been sold as a service since August 2019.

References
2021-07-27BlackberryBlackBerry Research & Intelligence Team
@techreport{team:20210727:old:3060d53, author = {BlackBerry Research & Intelligence Team}, title = {{Old Dogs New Tricks: Attackers Adopt Exotic Programming Languages}}, date = {2021-07-27}, institution = {Blackberry}, url = {https://www.blackberry.com/content/dam/blackberry-com/asset/enterprise/pdf/direct/report-old-dogs-new-tricks.pdf}, language = {English}, urldate = {2021-07-27} } Old Dogs New Tricks: Attackers Adopt Exotic Programming Languages
elf.wellmess ElectroRAT BazarNimrod Buer Cobalt Strike Remcos Snake TeleBot WellMess Zebrocy
2021-07-19FortinetVal Saengphaibul, Fred Gutierrez
@online{saengphaibul:20210719:signed:d9f809c, author = {Val Saengphaibul and Fred Gutierrez}, title = {{Signed, Sealed, and Delivered – Signed XLL File Delivers Buer Loader}}, date = {2021-07-19}, organization = {Fortinet}, url = {https://www.fortinet.com/blog/threat-research/signed-sealed-and-delivered-signed-xll-file-delivers-buer-loader}, language = {English}, urldate = {2021-07-26} } Signed, Sealed, and Delivered – Signed XLL File Delivers Buer Loader
Buer
2021-05-03Medium walmartglobaltechJoshua Platt, Jason Reaves
@online{platt:20210503:buerloader:2aa3e3f, author = {Joshua Platt and Jason Reaves}, title = {{BuerLoader Updates}}, date = {2021-05-03}, organization = {Medium walmartglobaltech}, url = {https://medium.com/walmartglobaltech/buerloader-updates-3e34c1949b96}, language = {English}, urldate = {2021-05-04} } BuerLoader Updates
Buer
2021-05-03ProofpointKelsey Merriman, Bryan Campbell, Selena Larson, Proofpoint Threat Research Team
@online{merriman:20210503:new:cd4d275, author = {Kelsey Merriman and Bryan Campbell and Selena Larson and Proofpoint Threat Research Team}, title = {{New Variant of Buer Loader Written in Rust}}, date = {2021-05-03}, organization = {Proofpoint}, url = {https://www.proofpoint.com/us/blog/threat-insight/new-variant-buer-loader-written-rust}, language = {English}, urldate = {2021-05-03} } New Variant of Buer Loader Written in Rust
Buer
2021-03Group-IBOleg Skulkin, Roman Rezvukhin, Semyon Rogachev
@techreport{skulkin:202103:ransomware:992ca10, author = {Oleg Skulkin and Roman Rezvukhin and Semyon Rogachev}, title = {{Ransomware Uncovered 2020/2021}}, date = {2021-03}, institution = {Group-IB}, url = {https://web.archive.org/web/20210305181115/https://cisoclub.ru/doc/otchet-kompanii-group-ib-ransomware-uncovered-2020-2021/?bp-attachment=group-ib_ransomware_uncovered_2020-2021.pdf}, language = {English}, urldate = {2021-06-16} } Ransomware Uncovered 2020/2021
RansomEXX BazarBackdoor Buer Clop Conti DoppelPaymer Dridex Egregor IcedID Maze PwndLocker QakBot RansomEXX REvil Ryuk SDBbot TrickBot Zloader
2021-02-25ANSSICERT-FR
@techreport{certfr:20210225:ryuk:7895e12, author = {CERT-FR}, title = {{Ryuk Ransomware}}, date = {2021-02-25}, institution = {ANSSI}, url = {https://www.cert.ssi.gouv.fr/uploads/CERTFR-2021-CTI-006.pdf}, language = {English}, urldate = {2021-03-02} } Ryuk Ransomware
BazarBackdoor Buer Conti Emotet Ryuk TrickBot
2021-02-02CRONUPGermán Fernández
@online{fernndez:20210202:de:6ff4f3a, author = {Germán Fernández}, title = {{De ataque con Malware a incidente de Ransomware}}, date = {2021-02-02}, organization = {CRONUP}, url = {https://www.cronup.com/post/de-ataque-con-malware-a-incidente-de-ransomware}, language = {Spanish}, urldate = {2021-03-02} } De ataque con Malware a incidente de Ransomware
Avaddon BazarBackdoor Buer Clop Cobalt Strike Conti DanaBot Dharma Dridex Egregor Emotet Empire Downloader FriedEx GootKit IcedID MegaCortex Nemty Phorpiex PwndLocker PyXie QakBot RansomEXX REvil Ryuk SDBbot SmokeLoader TrickBot Zloader
2021-01-09Marco Ramilli's BlogMarco Ramilli
@online{ramilli:20210109:command:d720b27, author = {Marco Ramilli}, title = {{Command and Control Traffic Patterns}}, date = {2021-01-09}, organization = {Marco Ramilli's Blog}, url = {https://marcoramilli.com/2021/01/09/c2-traffic-patterns-personal-notes/}, language = {English}, urldate = {2021-05-17} } Command and Control Traffic Patterns
ostap LaZagne Agent Tesla Azorult Buer Cobalt Strike DanaBot DarkComet Dridex Emotet Formbook IcedID ISFB NetWire RC PlugX Quasar RAT SmokeLoader TrickBot
2021SecureworksSecureWorks
@online{secureworks:2021:threat:07bd94a, author = {SecureWorks}, title = {{Threat Profile: GOLD SYMPHONY}}, date = {2021}, organization = {Secureworks}, url = {http://www.secureworks.com/research/threat-profiles/gold-symphony}, language = {English}, urldate = {2021-05-28} } Threat Profile: GOLD SYMPHONY
Buer GOLD SYMPHONY
2021SecureworksSecureWorks
@online{secureworks:2021:threat:4e7c443, author = {SecureWorks}, title = {{Threat Profile: GOLD BLACKBURN}}, date = {2021}, organization = {Secureworks}, url = {http://www.secureworks.com/research/threat-profiles/gold-blackburn}, language = {English}, urldate = {2021-05-28} } Threat Profile: GOLD BLACKBURN
Buer Dyre TrickBot WIZARD SPIDER
2020-11-20ZDNetCatalin Cimpanu
@online{cimpanu:20201120:malware:0b8ff59, author = {Catalin Cimpanu}, title = {{The malware that usually installs ransomware and you need to remove right away}}, date = {2020-11-20}, organization = {ZDNet}, url = {https://www.zdnet.com/article/the-malware-that-usually-installs-ransomware-and-you-need-to-remove-right-away/}, language = {English}, urldate = {2020-11-23} } The malware that usually installs ransomware and you need to remove right away
Avaddon BazarBackdoor Buer Clop Cobalt Strike Conti DoppelPaymer Dridex Egregor Emotet FriedEx MegaCortex Phorpiex PwndLocker QakBot Ryuk SDBbot TrickBot Zloader
2020-11-18Minerva LabsEddy Bobritsky
@online{bobritsky:20201118:stopping:e5c486b, author = {Eddy Bobritsky}, title = {{Stopping BuerLoader With Minerva Lab's Hostile Environment Simulation module}}, date = {2020-11-18}, organization = {Minerva Labs}, url = {https://blog.minerva-labs.com/stopping-buerloader}, language = {English}, urldate = {2020-11-19} } Stopping BuerLoader With Minerva Lab's Hostile Environment Simulation module
Buer
2020-11-09Area 1Threat Research Team
@online{team:20201109:phishing:a25a567, author = {Threat Research Team}, title = {{Phishing Campaign Threatens Job Security, Drops Bazar and Buer Malware}}, date = {2020-11-09}, organization = {Area 1}, url = {https://www.area1security.com/blog/trickbot-spear-phishing-drops-bazar-buer-malware/}, language = {English}, urldate = {2020-11-18} } Phishing Campaign Threatens Job Security, Drops Bazar and Buer Malware
BazarBackdoor Buer
2020-10-29Twitter (@SophosLabs)SophosLabs
@online{sophoslabs:20201029:similarities:408a640, author = {SophosLabs}, title = {{Tweet on similarities between BUER in-memory loader & RYUK in-memory loader}}, date = {2020-10-29}, organization = {Twitter (@SophosLabs)}, url = {https://twitter.com/SophosLabs/status/1321844306970251265}, language = {English}, urldate = {2020-11-02} } Tweet on similarities between BUER in-memory loader & RYUK in-memory loader
Buer Ryuk
2020-10-28SophosLabs UncutSean Gallagher, Peter Mackenzie, Elida Leite, Syed Shahram, Bill Kearny, Anand Ajjan, Brett Cove, Gabor Szappanos
@online{gallagher:20201028:hacks:8e1d051, author = {Sean Gallagher and Peter Mackenzie and Elida Leite and Syed Shahram and Bill Kearny and Anand Ajjan and Brett Cove and Gabor Szappanos}, title = {{Hacks for sale: inside the Buer Loader malware-as-a-service}}, date = {2020-10-28}, organization = {SophosLabs Uncut}, url = {https://news.sophos.com/en-us/2020/10/28/hacks-for-sale-inside-the-buer-loader-malware-as-a-service/}, language = {English}, urldate = {2020-11-02} } Hacks for sale: inside the Buer Loader malware-as-a-service
Buer Ryuk Zloader
2020-09-29ZscalerMohd Sadique, Atinderpal Singh
@online{sadique:20200929:spear:de79be6, author = {Mohd Sadique and Atinderpal Singh}, title = {{Spear Phishing Campaign Delivers Buer and Bazar Malware}}, date = {2020-09-29}, organization = {Zscaler}, url = {https://www.zscaler.com/blogs/research/spear-phishing-campaign-delivers-buer-and-bazar-malware}, language = {English}, urldate = {2020-10-15} } Spear Phishing Campaign Delivers Buer and Bazar Malware
BazarBackdoor Buer
2020-03-05Kaspersky LabsAMR
@online{amr:20200305:mokes:698295f, author = {AMR}, title = {{Mokes and Buerak distributed under the guise of security certificates}}, date = {2020-03-05}, organization = {Kaspersky Labs}, url = {https://securelist.com/mokes-and-buerak-distributed-under-the-guise-of-security-certificates/96324/}, language = {English}, urldate = {2020-03-09} } Mokes and Buerak distributed under the guise of security certificates
Buer Mokes
2019-12-05KrabsOnSecurityMr. Krabs
@online{krabs:20191205:buer:9c3cf72, author = {Mr. Krabs}, title = {{Buer Loader, new Russian loader on the market with interesting persistence}}, date = {2019-12-05}, organization = {KrabsOnSecurity}, url = {https://krabsonsecurity.com/2019/12/05/buer-loader-new-russian-loader-on-the-market-with-interesting-persistence/}, language = {English}, urldate = {2020-01-08} } Buer Loader, new Russian loader on the market with interesting persistence
Buer
2019-12-04ProofpointKelsey Merriman, Dennis Schwarz, Kafeine, Axel F
@online{merriman:20191204:buer:6c413aa, author = {Kelsey Merriman and Dennis Schwarz and Kafeine and Axel F}, title = {{Buer, a new loader emerges in the underground marketplace}}, date = {2019-12-04}, organization = {Proofpoint}, url = {https://www.proofpoint.com/us/threat-insight/post/buer-new-loader-emerges-underground-marketplace}, language = {English}, urldate = {2020-01-06} } Buer, a new loader emerges in the underground marketplace
Buer
2019-10-10Twitter (@StopMalvertisin)Kimberly
@online{kimberly:20191010:malware:032ed3c, author = {Kimberly}, title = {{Tweet on Malware Sample}}, date = {2019-10-10}, organization = {Twitter (@StopMalvertisin)}, url = {https://twitter.com/StopMalvertisin/status/1182505434231398401}, language = {English}, urldate = {2020-01-10} } Tweet on Malware Sample
Buer
Yara Rules
[TLP:WHITE] win_buer_auto (20210616 | Detects win.buer.)
rule win_buer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        version = "1"
        description = "Detects win.buer."
        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.buer"
        malpedia_rule_date = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 7cf1 eb02 33c0 5f 5e 5b 5d }
            // n = 7, score = 1100
            //   7cf1                 | jl                  0xfffffff3
            //   eb02                 | jmp                 4
            //   33c0                 | xor                 eax, eax
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx
            //   5d                   | pop                 ebp

        $sequence_1 = { 83e003 83e800 7435 83e801 7420 83e801 740b }
            // n = 7, score = 1100
            //   83e003               | and                 eax, 3
            //   83e800               | sub                 eax, 0
            //   7435                 | je                  0x37
            //   83e801               | sub                 eax, 1
            //   7420                 | je                  0x22
            //   83e801               | sub                 eax, 1
            //   740b                 | je                  0xd

        $sequence_2 = { 01515c 5f 5e 894154 5b c9 c3 }
            // n = 7, score = 1100
            //   01515c               | add                 dword ptr [ecx + 0x5c], edx
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   894154               | mov                 dword ptr [ecx + 0x54], eax
            //   5b                   | pop                 ebx
            //   c9                   | leave               
            //   c3                   | ret                 

        $sequence_3 = { 8b45dc 03c6 89414c 8b45fc 03c7 }
            // n = 5, score = 1100
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   03c6                 | add                 eax, esi
            //   89414c               | mov                 dword ptr [ecx + 0x4c], eax
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   03c7                 | add                 eax, edi

        $sequence_4 = { 8b55d8 894148 8b45dc 03c6 }
            // n = 4, score = 1100
            //   8b55d8               | mov                 edx, dword ptr [ebp - 0x28]
            //   894148               | mov                 dword ptr [ecx + 0x48], eax
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   03c6                 | add                 eax, esi

        $sequence_5 = { 03c2 8b55e8 015158 8b55d8 894148 }
            // n = 5, score = 1100
            //   03c2                 | add                 eax, edx
            //   8b55e8               | mov                 edx, dword ptr [ebp - 0x18]
            //   015158               | add                 dword ptr [ecx + 0x58], edx
            //   8b55d8               | mov                 edx, dword ptr [ebp - 0x28]
            //   894148               | mov                 dword ptr [ecx + 0x48], eax

        $sequence_6 = { 8b00 8b4010 8945fc 61 }
            // n = 4, score = 1100
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   8b4010               | mov                 eax, dword ptr [eax + 0x10]
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   61                   | popal               

        $sequence_7 = { 6803010000 ff75f8 ff15???????? 59 59 }
            // n = 5, score = 1100
            //   6803010000           | push                0x103
            //   ff75f8               | push                dword ptr [ebp - 8]
            //   ff15????????         |                     
            //   59                   | pop                 ecx
            //   59                   | pop                 ecx

        $sequence_8 = { b9???????? eb1a 6a05 59 }
            // n = 4, score = 200
            //   b9????????           |                     
            //   eb1a                 | jmp                 0x1c
            //   6a05                 | push                5
            //   59                   | pop                 ecx

        $sequence_9 = { b9e97f00d6 0fa3c1 7308 83c408 }
            // n = 4, score = 200
            //   b9e97f00d6           | mov                 ecx, 0xd6007fe9
            //   0fa3c1               | bt                  ecx, eax
            //   7308                 | jae                 0xa
            //   83c408               | add                 esp, 8

        $sequence_10 = { b9???????? eb05 b9???????? 8b1424 }
            // n = 4, score = 200
            //   b9????????           |                     
            //   eb05                 | jmp                 7
            //   b9????????           |                     
            //   8b1424               | mov                 edx, dword ptr [esp]

        $sequence_11 = { b9???????? e9???????? 8d9424a4000000 c70205000000 }
            // n = 4, score = 200
            //   b9????????           |                     
            //   e9????????           |                     
            //   8d9424a4000000       | lea                 edx, dword ptr [esp + 0xa4]
            //   c70205000000         | mov                 dword ptr [edx], 5

        $sequence_12 = { b9???????? e9???????? 8b8424a8000000 85c0 }
            // n = 4, score = 200
            //   b9????????           |                     
            //   e9????????           |                     
            //   8b8424a8000000       | mov                 eax, dword ptr [esp + 0xa8]
            //   85c0                 | test                eax, eax

        $sequence_13 = { b9???????? eb36 6a04 59 }
            // n = 4, score = 200
            //   b9????????           |                     
            //   eb36                 | jmp                 0x38
            //   6a04                 | push                4
            //   59                   | pop                 ecx

        $sequence_14 = { b9???????? e9???????? ff4608 89f1 }
            // n = 4, score = 200
            //   b9????????           |                     
            //   e9????????           |                     
            //   ff4608               | inc                 dword ptr [esi + 8]
            //   89f1                 | mov                 ecx, esi

        $sequence_15 = { e8???????? 0f0b 53 57 56 83ec0c }
            // n = 6, score = 200
            //   e8????????           |                     
            //   0f0b                 | ud2                 
            //   53                   | push                ebx
            //   57                   | push                edi
            //   56                   | push                esi
            //   83ec0c               | sub                 esp, 0xc

    condition:
        7 of them and filesize < 2518016
}
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