somehow yesterday night there was this file in my user-root-directory from out of nowhere (it came to live at a time where i was sleeping, exactly at 3:00 am): ArcDeviceInfo… its very small, less than 1KB.
i checked it for virusses and nothing was found. so i kinda feel relieved. but
- where does it come from
- what is it?
- do I need it?
pls find attached some of my infos you might need 
Server configuration detail
Operating system: Linux 4.9.35-v7+ #1014 SMP Fri Jun 30 14:47:43 BST 2017 armv7l
Webserver: Apache/2.4.25 (Raspbian) (fpm-fcgi)
Database: mysql 10.1.23
PHP version: 7.0.27-0+deb9u1
Modules loaded: Core, date, libxml, openssl, pcre, zlib, filter, hash, Reflection, SPL, session, standard, cgi-fcgi, mysqlnd, PDO, xml, apcu, calendar, ctype, curl, dom, mbstring, fileinfo, ftp, gd, gettext, iconv, igbinary, json, exif, mysqli, pdo_mysql, Phar, posix, readline, redis, shmop, SimpleXML, sockets, sysvmsg, sysvsem, sysvshm, tokenizer, wddx, xmlreader, xmlwriter, xsl, zip, Zend OPcache
Nextcloud version: 13.0.2 - 13.0.2.1
Updated from an older Nextcloud/ownCloud or fresh install: updated several times since 1 year
Where did you install Nextcloud from: flahed the image from ownyourbits.com
Signing status
Array
List of activated apps
Enabled:
- activity: 2.6.1
- admin_audit: 1.3.0
- admin_notifications: 1.0.1
- announcementcenter: 3.2.1
- apporder: 0.4.1
- audioplayer: 2.3.0
- bookmarks: 0.11.0
- bruteforcesettings: 1.0.3
- calendar: 1.6.1
- circles: 0.13.6
- cms_pico: 0.9.7
- comments: 1.3.0
- contacts: 2.1.3
- dav: 1.4.6
- drop_account: 0.0.6
- dropit: 0.1.1
- federatedfilesharing: 1.3.1
- federation: 1.3.0
- files: 1.8.0
- files_accesscontrol: 1.3.0
- files_downloadactivity: 1.2.0
- files_external: 1.4.1
- files_pdfviewer: 1.2.1
- files_rightclick: 0.8.4
- files_sharing: 1.5.0
- files_snapshots: 0.1.1
- files_texteditor: 2.5.1
- files_trashbin: 1.3.0
- files_videoplayer: 1.2.0
- firstrunwizard: 2.2.1
- flowupload: 0.0.7
- gallery: 18.0.0
- groupfolders: 1.2.0
- impersonate: 1.0.4
- issuetemplate: 0.3.0
- logreader: 2.0.0
- lookup_server_connector: 1.1.0
- mail: 0.7.10
- metadata: 0.6.0
- nextcloud_announcements: 1.2.0
- notifications: 2.1.2
- oauth2: 1.1.0
- ojsxc: 3.3.2
- ownbackup: 17.5.0
- password_policy: 1.3.0
- phonetrack: 0.2.7
- provisioning_api: 1.3.0
- quota_warning: 1.2.0
- rainloop: 5.0.6
- ransomware_protection: 1.1.0
- registration: 0.4.2
- serverinfo: 1.3.0
- sharebymail: 1.3.0
- socialsharing_email: 1.0.3
- socialsharing_facebook: 1.0.2
- socialsharing_twitter: 1.0.2
- spreed: 3.2.0
- tasks: 0.9.6
- theming: 1.4.1
- twofactor_backupcodes: 1.2.3
- updatenotification: 1.3.0
- user_usage_report: 1.0.1
- workflowengine: 1.3.0
Disabled:
- encryption
- files_versions
- radio
- survey_client
- systemtags
- user_external
- user_ldap
Configuration (config/config.php)
{
"passwordsalt": "***REMOVED SENSITIVE VALUE***",
"secret": "***REMOVED SENSITIVE VALUE***",
"trusted_domains": {
"0": "localhost",
"1": "192.168.xxx.yyy",
"2": "nextcloud.local",
"4": "cloud.mydomain.xy",
"5": "cloud.myotherdomain.xy"
},
"datadirectory": "***REMOVED SENSITIVE VALUE***",
"overwrite.cli.url": "https:\/\/cloud.mydomain.xy",
"dbtype": "mysql",
"version": "13.0.2.1",
"dbname": "***REMOVED SENSITIVE VALUE***",
"dbhost": "***REMOVED SENSITIVE VALUE***",
"dbport": "",
"dbtableprefix": "oc_",
"mysql.utf8mb4": true,
"dbuser": "***REMOVED SENSITIVE VALUE***",
"dbpassword": "***REMOVED SENSITIVE VALUE***",
"installed": true,
"instanceid": "***REMOVED SENSITIVE VALUE***",
"mail_smtpmode": "smtp",
"mail_smtpauthtype": "LOGIN",
"mail_smtpsecure": "ssl",
"mail_from_address": "***REMOVED SENSITIVE VALUE***",
"mail_domain": "***REMOVED SENSITIVE VALUE***",
"mail_smtpauth": 1,
"mail_smtphost": "***REMOVED SENSITIVE VALUE***",
"mail_smtpport": "465",
"mail_smtpname": "***REMOVED SENSITIVE VALUE***",
"mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
"loglevel": "2",
"maintenance": false,
"theme": "",
"updater.release.channel": "stable",
"memcache.local": "\\OC\\Memcache\\Redis",
"memcache.locking": "\\OC\\Memcache\\Redis",
"redis": {
"host": "***REMOVED SENSITIVE VALUE***",
"port": 0,
"timeout": 0,
"password": "***REMOVED SENSITIVE VALUE***"
},
"log_type": "file",
"defaultapp": "apporder"
}
Are you using external storage, if yes which one: yes, magentacloud.de via webdav
Are you using encryption: no
Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/…
Client configuration
Browser: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0
Operating system: Win 7 (64) pro