CyberSecBulletin
CVE-2021-30116Exploited in the wildNVD status: Analyzed

Kaseya Virtual System/Server Administrator (VSA) Information Disclosure

Published Updated By the CyberSecBulletin desk

CVE-2021-30116 is a critical-severity insufficiently protected credentials vulnerability in Vsa Agent from Kaseya, 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 version 9.5.0.24 as the first without the flaw, so updating Vsa Agent to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild, including in ransomware campaigns.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Vsa Agent to 9.5.0.24 or a later version.
  2. Update Vsa Server to 9.5.7a or a later version.
  3. CISA's required action: Apply updates per vendor instructions.
  4. Read the advisory on helpdesk.kaseya.com for workarounds and exact fixed builds.
  5. 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
KaseyaVsa Agentbefore 9.5.0.249.5.0.24
KaseyaVsa Serverbefore 9.5.7a9.5.7a

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 3.110.0CriticalCNA (mitre.org)
CVSS 3.19.8CriticalNVD
CVSS 2.07.5HighNVD

Official description

Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\Program Files (x86)\Kaseya\XXXXXXXXXX\KaseyaD.ini) which contains an Agent_Guid and AgentPassword This Agent_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813&pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- * Unauthenticated download page leaks credentials * Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents * dl.asp accepts credentials via a GET request * Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.

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

The underlying weakness: Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.

How developers prevent this class of flaw

  • Use an appropriate security mechanism to protect the credentials.
  • Make appropriate use of cryptography to protect the credentials.
  • Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).

More Insufficiently Protected Credentials vulnerabilities (CWE-522)

Timeline

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

References

Technical write-ups (may include proof of concept)

Recent Insufficiently Protected Credentials vulnerabilities

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