CyberSecBulletin
CVE-2021-40870Exploited in the wildNVD status: Analyzed

Aviatrix Controller Unrestricted Upload of File

Published Updated By the CyberSecBulletin desk

CVE-2021-40870 is a critical-severity relative path traversal vulnerability in Controller from Aviatrix, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 6.2.2043, 6.3.2490, 6.4.2838 as the first without the flaw, so updating Controller to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on January 18, 2022, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Controller to 6.2.2043 or 6.3.2490 or 6.4.2838 or 6.5.1922, whichever matches your release line, or a later version.
  2. CISA's required action: Apply updates per vendor instructions.
  3. Read the advisory on docs.aviatrix.com for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
AviatrixController6.2 up to, but not including, 6.2.2043; 6.3 up to, but not including, 6.3.2490; 6.4 up to, but not including, 6.4.2838; 6.5 up to, but not including, 6.5.19226.2.2043, 6.3.2490, 6.4.2838, 6.5.1922

Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)
CVSS 2.07.5HighNVD

Official description

An issue was discovered in Aviatrix Controller 6.x before 6.5-1804.1922. Unrestricted upload of a file with a dangerous type is possible, which allows an unauthenticated user to execute arbitrary code via directory traversal.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Relative Path Traversal

The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as.. that can resolve to a location that is outside of that directory.

How developers prevent this class of flaw

  • Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.

More Relative Path Traversal vulnerabilities (CWE-23)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Technical write-ups (may include proof of concept)

Other vulnerabilities in Controller

All Controller vulnerabilities

Spotted an error? Tell us.