Patchfirst
CVE-2022-23131 KEVPublic exploit Critical · 9.8 EPSS 95.7%

Zabbix Frontend Authentication Bypass Vulnerability

Zabbix · Frontend

Summary

The Zabbix Frontend contains an authentication bypass flaw in its SAML SSO authentication path, where a user login stored in session data is not verified and can therefore be modified. An unauthenticated remote attacker can exploit this when SAML authentication is enabled (a non-default setting) and they know a Zabbix username, or use the guest account if it has been enabled, to escalate privileges and gain admin access.

Official description · NVD

In the case of instances where the SAML SSO authentication is enabled (non-default), session data can be modified by a malicious actor, because a user login stored in the session was not verified. Malicious unauthenticated actor may exploit this issue to escalate privileges and gain admin access to Zabbix Frontend. To perform the attack, SAML authentication is required to be enabled and the actor has to know the username of Zabbix user (or use the guest account, which is disabled by default).

Breakdown
69.8 / 100
Exploited
Yes, in CISA KEV
Reports
0
Tactics
5/15

How an attack unfolds

Based on mappings. Select a step to see the evidence.
  1. How attackers get in

  2. What they do

  3. What can follow

First seen exploited 40 days after disclosure. Public exploit code (PoC-in-GitHub) appeared 36 days after disclosure.

  1. Disclosedday 0
  2. Public exploit codePoC-in-GitHub+36 days
  3. First seen exploitedVulnCheck KEV evidenceAdded to CISA KEVEU database agrees+40 days

CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.

techniques

4 , grouped by in kill-chain order 4

Initial AccessTA0001

Valid Accounts T1078 also Persistence, Privilege Escalation, Stealth
MITRE CTID mapping of the KEV entry · follow-on activity

This vulnerability is exploited by a malicious actor via improper validation via SAML to modify session data and escalate privileges to gain admin access to the Zabbix Frontend. This allows attackers to control the saml_data[username_attribute] value. This flaw enables unauthenticated users to bypass authentication and access the Zabbix dashboard as a highly-privileged user, such as the default "Admin" user. Additionally, incorrect handling of Zabbix installer files permits unauthenticated users to access and reconfigure servers.

MITRE CTID mapping of the KEV entry · how it is exploited

ExecutionTA0002

MITRE CTID mapping of the KEV entry · follow-on activity

Privilege EscalationTA0004

MITRE CTID mapping of the KEV entry · primary impact

Detection

0 rules for this CVE · 324 general rules for its techniques

Rules for this CVE

0 that reference CVE-2022-23131 directly.

CVE-specific rules are not available in this build. Search SigmaHQ ↗

General rules for this CVE’s techniques

These detect the technique in general, not this specific vulnerability.

Exploit Public-Facing ApplicationT1190149 general rules
Abuse Elevation Control MechanismT154824 general rules
Valid AccountsT107856 general rules
Command and Scripting InterpreterT105995 general rules

Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.

What security researchers reported

Not named in any threat report yet

Also mentioned in 50 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

2 links, grouped by NVD tag (1 duplicate merged)
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