cbcvebase.
CVE-2017-3819
published 2017-03-15

CVE-2017-3819: A privilege escalation vulnerability in the Secure Shell (SSH) subsystem in the StarOS operating system for Cisco ASR 5000 Series, ASR 5500 Series, ASR 5700…

PriorityP261high8.8CVSS 3.0
AVNACLPRLUINSUCHIHAH
EPSS
3.26%
86.8th percentile
A privilege escalation vulnerability in the Secure Shell (SSH) subsystem in the StarOS operating system for Cisco ASR 5000 Series, ASR 5500 Series, ASR 5700 Series devices, and Cisco Virtualized Packet Core could allow an authenticated, remote attacker to gain unrestricted, root shell access. The vulnerability is due to missing input validation of parameters passed during SSH or SFTP login. An attacker could exploit this vulnerability by providing crafted user input to the SSH or SFTP command-line interface (CLI) during SSH or SFTP login. An exploit could allow an authenticated attacker to gain root privileges access on the router. Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability can be triggered via both IPv4 and IPv6 traffic. An established TCP connection toward port 22, the SSH default port, is needed to perform the attack. The attacker must have valid credentials to login to the system via SSH or SFTP. The following products have been confirmed to be vulnerable: Cisco ASR 5000/5500/5700 Series devices running StarOS after 17.7.0 and prior to 18.7.4, 19.5, and 20.2.3 with SSH configured are vulnerable. Cisco Virtualized Packet Core - Single Instance (VPC-SI) and Distributed Instance (VPC-DI) devices running StarOS prior to N4.2.7 (19.3.v7) and N4.7 (20.2.v0) with SSH configured are vulnerable. Cisco Bug IDs: CSCva65853.

Affected

25 ranges
VendorProductVersion rangeFixed in
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscoasr_5000_series_software
ciscostaros_ssh
ciscovirtualized_packet_core
ciscovirtualized_packet_core
ciscovirtualized_packet_core

Detection & IOCsextracted from sources · hover to see the quote

  • Monitor for SSH/SFTP login attempts to Cisco StarOS devices (ASR 5000/5500/5700, VPC-SI, VPC-DI) with crafted/anomalous input parameters in the CLI during authentication, which may indicate privilege escalation exploitation.
  • Alert on unexpected root shell access obtained via SSH or SFTP sessions on affected Cisco StarOS devices, as successful exploitation grants unrestricted root shell access.
  • Scope detection to inbound TCP port 22 traffic directed at affected devices; both IPv4 and IPv6 traffic vectors must be monitored.
  • ·Vulnerability is only exploitable if SSH is configured on the device. Devices without SSH configured are not affected.
  • ·Exploitation requires valid credentials; unauthenticated attackers cannot trigger this vulnerability.
  • ·Only traffic directed to the affected system can be used to exploit this vulnerability; transit traffic is not a vector.
  • ·No workarounds are available; patching to fixed StarOS versions (18.7.4, 19.5, 20.2.3, N4.2.7/19.3.v7, N4.7/20.2.v0) is the only mitigation.

CVSS provenance

nvdv3.08.8HIGHCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.09.0CRITICALAV:N/AC:L/Au:S/C:C/I:C/A:C
vendor_cisco8.8HIGH
vendor_redhat6.1MEDIUM
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