It was discovered that there was a potential remote code execution via deserialization in tomcat7, a server for HTTP and Java "servlets".
When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is configured with sessionAttributeValueClassNameFilter="null" (the default unless a SecurityManager is used) or a sufficiently lax filter to allow the attacker provided object to be deserialized; and d) the attacker knows the relative file path from the storage location used by FileStore to the file the attacker has control over; then, using a specifically crafted request, the attacker will be able to trigger remote code execution via deserialization of the file under their control. Note that all of conditions a) to d) must be true for the attack to succeed.
For Debian 8 Jessie
, these problems have been fixed in version
7.0.56-3+really7.0.100-1+deb8u1.
We recommend that you upgrade your tomcat7 packages.
Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS