cbcvebase.
CVE-2018-6328
published 2018-03-14

CVE-2018-6328: It was discovered that the Unitrends Backup (UB) before 10.1.0 user interface was exposed to an authentication bypass, which then could allow an…

PriorityP184critical9.8CVSS 3.0
AVNACLPRNUINSUCHIHAH
EXPLOIT
EPSS
65.52%
99.2th percentile
It was discovered that the Unitrends Backup (UB) before 10.1.0 user interface was exposed to an authentication bypass, which then could allow an unauthenticated user to inject arbitrary commands into its /api/hosts parameters using backquotes.

Affected

1 ranges
VendorProductVersion rangeFixed in
kaseyaunitrends_backup< 10.110.1

Detection & IOCsextracted from sources · hover to see the quote

url/api/hosts/
url/api/systems/details
otherv0:b' UNION SELECT -1 -- :1:/usr/bp/logs.dir/gui_root.log:0
otherv0:b' UNION SELECT -1 -- :1:/usr/bp/logs.dir/gui_root.log:0
path/usr/bp/logs.dir/gui_root.log
port1743
  • Detect POST requests to /api/hosts/ or /api/storage with an AuthToken header containing a base64-encoded SQLi bypass string (decodes to contain UNION SELECT -1).
  • Detect HTTP requests to /api/hosts/ or /api/storage with the X-Requested-With: XMLHttpRequest header and an AuthToken header simultaneously — characteristic of this exploit's authentication bypass.
  • Monitor for outbound ncat bind-shell connections on random ports in the 4000–5000 range originating from the Unitrends web server process (apache).
  • Monitor for creation of randomly named 16-character .py files in /tmp on Unitrends appliances, followed by their execution via python and subsequent deletion.
  • Detect GET requests to /api/systems/details with an AuthToken header as a pre-exploitation check probe against Unitrends UEB.
  • Monitor xinetd port 1743 for unexpected local connections from the apache/web process, which is used by the privilege escalation stage to communicate with the bpd daemon.
  • ·The exploit targets UEB v9 via /api/storage (runs as root) and UEB v10 via /api/hosts (runs as limited/apache user); detection rules should cover both endpoints.
  • ·The Metasploit module defaults to PAYLOAD linux/x86/meterpreter/reverse_tcp with SSL enabled on port 443; network detections should account for encrypted HTTPS traffic.
  • ·The bind-shell port used in Stage 1 is randomized between 4000 and 5000 per exploit run, so port-specific firewall rules will not reliably block this stage.

CVSS provenance

nvdv3.09.8CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
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