Atlassian Confluence Data Center and Server Template Injection
CVE-2023-22527 is a critical-severity improper neutralization of special elements in output used by a downstream component vulnerability in Confluence Data Center from Atlassian, 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 8.5.4 as the first without the flaw, so updating Confluence Data Center to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on January 24, 2024, which means attacks have been observed in the wild, including in ransomware campaigns.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Confluence Data Center to 8.5.4 or a later version.
- Update Confluence Server to 8.5.4 or a later version.
- CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Read the advisory on confluence.atlassian.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Atlassian | Confluence Data Center | >= 8.0.0; >= 8.1.0; >= 8.2.0; >= 8.3.0; >= 8.4.0; >= 8.5.0; >= 8.5.1; >= 8.5.2; and 2 more ranges | 8.5.4 |
| Atlassian | Confluence Server | >= 8.0.0; >= 8.1.0; >= 8.2.0; >= 8.3.0; >= 8.4.0; >= 8.5.0; >= 8.5.1; >= 8.5.2; and 2 more ranges | 8.5.4 |
Version data comes from the organisation that assigned the CVE. 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 system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 3.0 | 10.0 | Critical | CNA (atlassian.com) |
Official description
A template injection vulnerability on older versions of Confluence Data Center and Server allows an unauthenticated attacker to achieve RCE on an affected instance. Customers using an affected version must take immediate action. Most recent supported versions of Confluence Data Center and Server are not affected by this vulnerability as it was ultimately mitigated during regular version updates. However, Atlassian recommends that customers take care to install the latest version to protect their instances from non-critical vulnerabilities outlined in Atlassian’s January Security Bulletin.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements in Output Used by a Downstream Component
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
How developers prevent this class of flaw
- Programming languages and supporting technologies might be chosen which are not subject to these issues.
- Utilize an appropriate mix of allowlist and denylist parsing to filter control-plane syntax from all input.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-22527US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/176789/Atlassian-Confluence-SSTI-Injection.htmlExploit, Third Party Advisory, VDB Entry
- vicarius.io/vsociety/posts/pwning-confluence-via-ognl-injection-for-fun-and-learning-cve-2023-22527Exploit
Other vulnerabilities in Confluence Data Center
- 7.5 High severity
- 7.1 High severity
- 7.1 High severity
- 9.3 Critical severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Neutralization of Special Elements in Output Used by a Downstream Component vulnerabilities
- 9.8 Critical severity
- 7.6 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 9.6 Critical severity
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