CVE-2021-27850
Apache Tapestry Remote Code Execution Bypass
Description
A critical unauthenticated remote code execution vulnerability was found all recent versions of Apache Tapestry. The affected versions include 5.4.5, 5.5.0, 5.6.2 and 5.7.0. The vulnerability I have found is a bypass of the fix for CVE-2019-0195. Recap: Before the fix of CVE-2019-0195 it was possible to download arbitrary class files from the classpath by providing a crafted asset file URL. An attacker was able to download the file `AppModule.class` by requesting the URL `http://localhost:8080/assets/something/services/AppModule.class` which contains a HMAC secret key. The fix for that bug was a blacklist filter that checks if the URL ends with `.class`, `.properties` or `.xml`. Bypass: Unfortunately, the blacklist solution can simply be bypassed by appending a `/` at the end of the URL: `http://localhost:8080/assets/something/services/AppModule.class/` The slash is stripped after the blacklist check and the file `AppModule.class` is loaded into the response. This class usually contains the HMAC secret key which is used to sign serialized Java objects. With the knowledge of that key an attacker can sign a Java gadget chain that leads to RCE (e.g. CommonsBeanUtils1 from ysoserial). Solution for this vulnerability: * For Apache Tapestry 5.4.0 to 5.6.1, upgrade to 5.6.2 or later. * For Apache Tapestry 5.7.0, upgrade to 5.7.1 or later.
INFO
Published Date :
April 15, 2021, 8:15 a.m.
Last Modified :
June 2, 2021, 3:15 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
5.9
Exploitability Score :
3.9
Public PoC/Exploit Available at Github
CVE-2021-27850 has a 14 public PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-27850.
| URL | Resource |
|---|---|
| http://www.openwall.com/lists/oss-security/2021/04/15/1 | Exploit Mailing List Third Party Advisory |
| https://lists.apache.org/thread.html/r237ff7f286bda31682c254550c1ebf92b0ec61329b32fbeb2d1c8751%40%3Cusers.tapestry.apache.org%3E | Mailing List Vendor Advisory |
| https://security.netapp.com/advisory/ntap-20210528-0002/ | Third Party Advisory |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
All CVE - PoC in GitHub
poc proofofconcept tester allcve cvegithub cvenew cvepoc cveupdate
None
在公网收集的gobypoc+部分自己加的poc
None
None
None
Java CVE Vulnerability Environment
cve java dubbo apache spring
Java HTML PLpgSQL Python JavaScript CSS Shell Dockerfile
CVE-2021-27850 ysoserial
None
Apache Tapestry CVE-2021-27850 PoC
Java
A Proof of concept for CVE-2021-27850 affecting Apache Tapestry and leading to unauthencticated remote code execution.
Java HTML JavaScript CSS
A Proof of concept for CVE-2021-27850 affecting Apache Tapestry and leading to unauthencticated remote code execution.
Java HTML JavaScript CSS
Automatic monitor github cve using Github Actions
Python
essential templates for kenzer [DEPRECATED]
kenzer vulnerabilities kenzer-templates arpsyndicate
Python Shell Ruby
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-27850 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-27850 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Modified Analysis by [email protected]
Jun. 02, 2021
Action Type Old Value New Value Changed Reference Type https://security.netapp.com/advisory/ntap-20210528-0002/ No Types Assigned https://security.netapp.com/advisory/ntap-20210528-0002/ Third Party Advisory -
CVE Modified by [email protected]
May. 28, 2021
Action Type Old Value New Value Added Reference https://security.netapp.com/advisory/ntap-20210528-0002/ [No Types Assigned] -
Initial Analysis by [email protected]
Apr. 22, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:C/I:C/A:C) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Changed Reference Type http://www.openwall.com/lists/oss-security/2021/04/15/1 No Types Assigned http://www.openwall.com/lists/oss-security/2021/04/15/1 Exploit, Mailing List, Third Party Advisory Changed Reference Type https://lists.apache.org/thread.html/r237ff7f286bda31682c254550c1ebf92b0ec61329b32fbeb2d1c8751%40%3Cusers.tapestry.apache.org%3E No Types Assigned https://lists.apache.org/thread.html/r237ff7f286bda31682c254550c1ebf92b0ec61329b32fbeb2d1c8751%40%3Cusers.tapestry.apache.org%3E Mailing List, Vendor Advisory Added CWE NIST CWE-502 Added CPE Configuration OR *cpe:2.3:a:apache:tapestry:*:*:*:*:*:*:*:* versions from (including) 5.4.0 up to (excluding) 5.6.2 *cpe:2.3:a:apache:tapestry:*:*:*:*:*:*:*:* versions from (including) 5.7.0 up to (excluding) 5.7.1 -
CVE Modified by [email protected]
Apr. 15, 2021
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2021/04/15/1 [No Types Assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-27850 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-27850
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
97.40 }} 0.01%
score
0.99940
percentile