cbcvebase.
CVE-2015-8103
published 2015-11-25

CVE-2015-8103: The Jenkins CLI subsystem in Jenkins before 1.638 and LTS before 1.625.2 allows remote attackers to execute arbitrary code via a crafted serialized Java…

PriorityP184critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EXPLOIT
EPSS
86.71%
99.7th percentile
The Jenkins CLI subsystem in Jenkins before 1.638 and LTS before 1.625.2 allows remote attackers to execute arbitrary code via a crafted serialized Java object, related to a problematic webapps/ROOT/WEB-INF/lib/commons-collections-*.jar file and the "Groovy variant in 'ysoserial'".

Affected

6 ranges
VendorProductVersion rangeFixed in
jenkinsjenkins< 1.625.21.625.2
jenkinsjenkins< 1.6381.638
jenkinsjenkins_core
jenkinsjenkins_lts
redhatopenshift_container_platform
redhatopenshift_container_platform

Detection & IOCsextracted from sources · hover to see the quote

pathwebapps/ROOT/WEB-INF/lib/commons-collections-*.jar
port8080
port4444
pathdata/exploits/CVE-2015-8103/serialized_file_writer
pathdata/exploits/CVE-2015-8103/serialized_class_loader
pathdata/exploits/CVE-2015-8103/serialized_jenkins_header
otherX-Jenkins-CLI-Port
otherX-Jenkins
othermetasploit.Payload
  • Detect exploitation attempts by monitoring for the HTTP response header 'X-Jenkins-CLI-Port', which the exploit checks to confirm the CLI port is exposed and the target is vulnerable.
  • Monitor for unauthenticated TCP connections to the Jenkins CLI RMI port (discovered via X-Jenkins-CLI-Port header) followed by transmission of a serialized Java stream — this is the exploit delivery channel.
  • Alert on creation of random-named .jar files in /tmp (or the configured TEMP directory) on Jenkins hosts, as the exploit stages a payload JAR to a random filename in that directory.
  • Detect the presence of the vulnerable commons-collections JAR in the Jenkins WEB-INF/lib directory as a configuration/file-integrity indicator.
  • Monitor for outbound connections from Jenkins processes to unexpected hosts on port 4444, consistent with a reverse netcat shell established post-exploitation.
  • Flag Jenkins versions at or below 1.637 (the explicit exploit target) as vulnerable; check the X-Jenkins response header value.
  • ·The exploit requires the Jenkins CLI port to be exposed (advertised via the X-Jenkins-CLI-Port HTTP response header). Disabling or firewalling the CLI port removes the primary attack surface.
  • ·Authentication is not required to exploit this vulnerability — any network-reachable Jenkins instance with the CLI port open is at risk.
  • ·The exploit uses the ysoserial CommonsCollections gadget chain; the vulnerable commons-collections JAR must be present in the Jenkins classpath for exploitation to succeed.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
vendor_redhat9.8CRITICAL
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