CVE-2018-1000861
Jenkins Stapler Web Framework Deserialization of Untrusted Data Vulnerability
Description
CVE-2018-1000861 is a CRITICAL deserialization of untrusted data vulnerability affecting Jenkins Jenkins Stapler Web Framework, carrying a CVSS 3.1 score of 9.8. A code execution vulnerability exists in the Stapler web framework used by Jenkins Affected products include Jenkins Jenkins (<= 2.138.3; <= 2.153), Redhat Openshift Container Platform (3.11). This CVE is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of 2022-08-10. With an EPSS score of 0.94467 (100th percentile), this vulnerability demonstrates significant real-world exploitation activity and should be prioritized for immediate remediation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| jenkins | jenkins | <= 2.138.3; <= 2.153 |
| redhat | openshift container platform | 3.11 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- http://packetstormsecurity.com/files/166778/Jenkins-Remote-Code-Execution.html(Third Party Advisory, VDB Entry)
- http://www.securityfocus.com/bid/106176(Broken Link)
- https://access.redhat.com/errata/RHBA-2019:0024(Third Party Advisory)
- https://jenkins.io/security/advisory/2018-12-05/#SECURITY-595(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-1000861(US Government Resource)
Weakness Type
CWE-502: Deserialization of Untrusted Data
CVE-2018-1000861 is classified under CWE-502 — Deserialization of Untrusted Data. Deserialization of Untrusted Data occurs when an application deserializes data from an untrusted source without sufficient verification that the resulting data will be valid and safe. Serialization converts objects into a format for storage or transmission; deserialization reconstructs objects from this format. When attackers control serialized data, they can manipulate it to instantiate arbitrary objects, set malicious property values, or trigger dangerous operations during the deserialization process. This frequently leads to remote code execution, as many programming languages allow objects to execute code during deserialization.
In the context of Jenkins Jenkins Stapler Web Framework, this weakness is particularly concerning because Deserialization vulnerabilities are among the most severe, consistently enabling remote code execution with no authentication required. Java, PHP, Python (pickle), .NET, and Ruby applications are commonly affected. The 2017 Equifax breach leveraged Apache Struts deserialization. Organizations using affected versions should understand that this vulnerability class has historically enabled severe compromises across enterprise environments.
Impact Analysis
CVE-2018-1000861 carries a CVSS 3.1 score of 9.8 (CRITICAL) with Unchanged Scope.
Confidentiality (HIGH): Successful exploitation grants the attacker extensive access to sensitive data processed by Jenkins Jenkins Stapler Web Framework, including configuration files, credentials, and potentially data from connected systems.
Integrity (HIGH): Attackers can modify critical system files, install backdoors, alter configurations, or deploy malware on affected systems running Jenkins Jenkins Stapler Web Framework.
Availability (HIGH): Complete disruption of the affected service or system is possible, including denial of service, system crashes, or rendering the product inoperable.
Scope Unchanged: The vulnerability's scope is Unchanged (U), meaning exploitation is contained within the vulnerable component. The impact, while significant, is limited to the Jenkins Jenkins Stapler Web Framework environment itself.
With an EPSS score of 0.94467 (100th percentile), this vulnerability ranks among the most likely to be exploited in real-world attacks, underscoring the urgency of remediation.
Exploit Maturity
CVE-2018-1000861 has confirmed active exploitation in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog.
Exploit status: This vulnerability has been actively exploited, as confirmed by its inclusion in the KEV catalog. The EPSS score of 0.94467 (100th percentile) places it among the most exploited vulnerabilities tracked.
Ransomware association: As of the latest KEV data, no direct ransomware association has been confirmed for CVE-2018-1000861. However, the confirmed exploitation in the wild means threat actors are actively using this vulnerability in attacks.
Attack surface: While specific public exploit code may not be readily available, the vulnerability's high EPSS score and KEV listing confirm that threat actors have developed and used working exploits. Organizations should assume exploitation tools exist in underground markets and private threat actor toolkits.
KEV deadline: CISA required federal agencies to remediate this vulnerability by 2022-08-10. All organizations should treat this deadline as a strong recommendation for their own remediation timelines.
Remediation
- Apply vendor patches immediately. Apply updates per vendor instructions. Consult the vendor advisory at jenkins.io for specific patch guidance.
- Verify affected product versions in your environment. Identify all instances of Jenkins Jenkins Stapler Web Framework in your infrastructure (affected versions: Jenkins Jenkins (<= 2.138.3; <= 2.153), Redhat Openshift Container Platform (3.11)). Use asset inventory and vulnerability scanning tools to ensure no instances are missed.
- Implement interim mitigations if patching is delayed. If immediate patching is not feasible, apply network-level controls such as restricting access to the affected component, enabling enhanced logging, and monitoring for indicators of compromise.
- Scan for signs of prior exploitation. Given the confirmed active exploitation of this vulnerability, review system logs and security monitoring data for evidence of compromise. Conduct a thorough investigation if any suspicious activity is detected.
- Update detection signatures and monitoring rules. Ensure intrusion detection and prevention systems, endpoint detection tools, and SIEM rules are updated to detect exploitation attempts targeting CVE-2018-1000861.
- Conduct a post-remediation review. After patching, verify the fix is effective and document the remediation actions taken. Update your vulnerability management records and assess whether any additional hardening measures are warranted.
Technical Details
CVE-2018-1000861 is a CRITICAL-severity vulnerability in Jenkins Jenkins Stapler Web Framework that can be exploited remotely over the network without physical access. The attack complexity is low, meaning no specialized conditions or preparation are required beyond the attack prerequisites. No prior authentication or privileges are needed to initiate the attack. No user interaction is required, allowing fully automated exploitation once the target is accessible.
Technical mechanism: A code execution vulnerability exists in the Stapler web framework used by Jenkins The underlying flaw relates to deserialization of untrusted data, where Deserialization of Untrusted Data occurs when an application deserializes data from an untrusted source without sufficient verification that the resulting data will be valid and safe. Serialization converts objects into a format for storage or transmission; deserialization reconstructs objects from this format.
CVSS 3.1 vector analysis: The vector reflects an Attack Vector of NETWORK, Attack Complexity of LOW, Privileges Required of NONE, User Interaction of NONE, Scope UNCHANGED, and impact ratings of HIGH/HIGH/HIGH for Confidentiality/Integrity/Availability respectively. The Unchanged scope means impact is contained within the vulnerable component itself.
Frequently Asked Questions
What is CVE-2018-1000861?
CVE-2018-1000861 is a CRITICAL-severity vulnerability (CVSS 9.8) in Jenkins Jenkins Stapler Web Framework that a code execution vulnerability exists in the Stapler web framework used by Jenkins. It is listed in CISA's Known Exploited Vulnerabilities catalog, confirming real-world exploitation.
Which products are affected by CVE-2018-1000861?
The affected products include Jenkins Jenkins (<= 2.138.3; <= 2.153), Redhat Openshift Container Platform (3.11). Organizations running any of these versions should verify their exposure and prioritize remediation. Check vendor advisories for the complete and most current list of affected versions.
How do I fix CVE-2018-1000861?
Apply updates per vendor instructions. Ensure all affected instances of Jenkins Jenkins Stapler Web Framework are identified using vulnerability scanning and asset management tools. If immediate patching is not possible, implement network-level mitigations and enhanced monitoring. After patching, verify the fix and scan for indicators of prior compromise.
How severe is CVE-2018-1000861?
CVE-2018-1000861 is rated CRITICAL with a CVSS 3.1 score of 9.8. Its EPSS score of 0.94467 places it in the 100th percentile for exploitation likelihood. The vulnerability has confirmed active exploitation in the wild and was required to be remediated by federal agencies by 2022-08-10 per CISA's KEV directive.
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