A lately disclosed safety flaw impacting Apache Tomcat has come underneath energetic exploitation within the wild following the discharge of a public proof-of-concept (PoC) a mere 30 hours after public disclosure.
The vulnerability, tracked as CVE-2025-24813, impacts the beneath variations –
- Apache Tomcat 11.0.0-M1 to 11.0.2
- Apache Tomcat 10.1.0-M1 to 10.1.34
- Apache Tomcat 9.0.0-M1 to 9.0.98
It considerations a case of distant code execution or data disclosure when particular circumstances are met –
- Writes enabled for the default servlet (disabled by default)
- Assist for partial PUT (enabled by default)
- A goal URL for safety delicate uploads that could be a sub-directory of a goal URL for public uploads
- Attacker information of the names of safety delicate information being uploaded
- The safety delicate information are additionally being uploaded through partial PUT
Profitable exploitation might allow a malicious person to view safety delicate information or inject arbitrary content material into these information by the use of a PUT request.
Moreover, an attacker might obtain distant code execution if all the next circumstances are true –
- Writes enabled for the default servlet (disabled by default)
- Assist for partial PUT (enabled by default)
- Utility was utilizing Tomcat’s file primarily based session persistence with the default storage location
- Utility included a library that could be leveraged in a deserialization assault
In an advisory launched final week, the venture maintainers stated the vulnerability has been resolved in Tomcat variations 9.0.99, 10.1.35, and 11.0.3.
However in a regarding twist, the vulnerability is already seeing exploitation makes an attempt within the wild, per Wallarm.
“This assault leverages Tomcat’s default session persistence mechanism together with its assist for partial PUT requests,” the corporate stated.
“The exploit works in two steps: The attacker uploads a serialized Java session file through PUT request. The attacker triggers deserialization by referencing the malicious session ID in a GET request.”
Put in another way, the assaults entail sending a PUT request containing a Base64-encoded serialized Java payload that is written to Tomcat’s session storage listing, which subsequently will get executed throughout deserialization by sending a GET request with the JSESSIONID pointing to the malicious session.
Wallarm additionally famous that the vulnerability is trivial to use and requires no authentication. The one prerequisite is that Tomcat makes use of file-based session storage.
“Whereas this exploit abuses session storage, the larger challenge is partial PUT dealing with in Tomcat, which permits importing virtually any file wherever,” it added. “Attackers will quickly begin shifting their techniques, importing malicious JSP information, modifying configurations, and planting backdoors exterior session storage.”
Customers working affected variations of Tomcat are suggested to replace their situations as quickly as potential to mitigate potential threats.
