cbcvebase.
CVE-2020-9484
published 2022-01-27

CVE-2020-9484: The fix for bug CVE-2020-9484 introduced a time of check, time of use vulnerability into Apache Tomcat 10.1.0-M1 to 10.1.0-M8, 10.0.0-M5 to 10.0.14, 9.0.35 to…

PriorityP261high7CVSS 3.1
AVLACHPRLUINSUCHIHAH
EXPLOIT
EPSS
56.64%
99.0th percentile
The fix for bug CVE-2020-9484 introduced a time of check, time of use vulnerability into Apache Tomcat 10.1.0-M1 to 10.1.0-M8, 10.0.0-M5 to 10.0.14, 9.0.35 to 9.0.56 and 8.5.55 to 8.5.73 that allowed a local attacker to perform actions with the privileges of the user that the Tomcat process is using. This issue is only exploitable when Tomcat is configured to persist sessions using the FileStore.

Affected

74 ranges· showing 25
VendorProductVersion rangeFixed in
apachetomcat
apachetomcat
apachetomcat
apachetomcat
apachetomcat10.0.1 – 10.0.14
apachetomcat>= 7.0.0 < 7.0.1087.0.108
apachetomcat7.0.0 – 7.0.107
apachetomcat>= 8.5.0 < 8.5.638.5.63
apachetomcat8.5.0 – 8.5.61
apachetomcat8.5.55 – 8.5.73
apachetomcat9.0.0 – 9.0.41
apachetomcat>= 9.0.1 < 9.0.439.0.43
apachetomcat9.0.35 – 9.0.56
apache_software_foundationapache_tomcat
apache_software_foundationapache_tomcat
apache_software_foundationapache_tomcat
apache_software_foundationapache_tomcat
canonicalubuntu_linux
canonicalubuntu_linux
debiandebian_linux
debiandebian_linux
debiandebian_linux
debiandebian_linux
debiantomcat9< tomcat9 9.0.43-1 (bookworm)tomcat9 9.0.43-1 (bookworm)
debiantomcat9< tomcat9 9.0.35-1 (bookworm)tomcat9 9.0.35-1 (bookworm)

Detection & IOCsextracted from sources · hover to see the quote

cookieJSESSIONID=../../../../../usr/local/tomcat/groovy
  • HTTP 500 response combined with body containing 'Exception', 'ObjectInputStream', and 'PersistentManagerBase' indicates successful deserialization trigger via crafted JSESSIONID cookie path traversal.
  • Exploit requires a crafted JSESSIONID cookie value containing a relative path traversal sequence pointing to an attacker-controlled file on the server (e.g., ../../../../../usr/local/tomcat/groovy). Monitor for JSESSIONID values containing path traversal sequences ('..') in HTTP request headers.
  • Attack is only exploitable when Tomcat is configured to use PersistenceManager with a FileStore and sessionAttributeValueClassNameFilter="null". Audit Tomcat configurations for this combination.
  • Shodan/FOFA queries can identify exposed Apache Tomcat instances as potential targets: search for title:'Apache Tomcat' or body containing 'apache tomcat'.
  • The incomplete fix (CVE-2021-25329) means Tomcat 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41, 8.5.0 to 8.5.61, and 7.0.0 to 7.0.107 may still be vulnerable under edge-case configurations even after the CVE-2020-9484 patch.
  • ·All four conditions must be simultaneously true for exploitation: attacker controls a file on the server, FileStore is configured, sessionAttributeValueClassNameFilter is null or lax, and attacker knows the relative file path to their controlled file.
  • ·CVE-2022-23181 (TOCTOU) is only exploitable when Tomcat is configured to persist sessions using the FileStore — same prerequisite as CVE-2020-9484.
  • ·Red Hat Certificate System 10 and Identity Management use pki-servlet-engine with a vulnerable Tomcat version, but are not exploitable in supported configurations because PersistentManager is not set and a SecurityManager is used.

CVSS provenance

nvdv3.17.0HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.04.4MEDIUMAV:L/AC:M/Au:N/C:P/I:P/A:P
ghsa7.0HIGH
osv7.5HIGH
vendor_ubuntu7.5HIGH
vendor_apache7.0LOW
vendor_debian7.0HIGH
vendor_oracle7.0HIGH
vendor_redhat7.0HIGH
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