Bug 1733073 (CVE-2019-0203)

Summary: CVE-2019-0203 subversion: NULL pointer dereference in svnserve leading to an unauthenticated remote DoS
Product: [Other] Security Response Reporter: msiddiqu
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: huzaifas, jorton, luhliari, security-response-team, vanmeeuwen+fedora
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: subversion 1.12.2, subversion 1.10.6, subversion 1.9.12 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in subversion. A remote, unauthenticated user can cause a null-pointer-dereference in svnserve by sending a certain sequences of protocol commands to the server. This results in a denial of service in some server configurations, specifically when anonymous access is enabled. The highest threat from this vulnerability is to system availability.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2019-08-15 20:47:01 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1733439, 1733440, 1733441, 1733442, 1733443, 1735579    
Bug Blocks: 1733096    

Description msiddiqu 2019-07-25 07:25:06 UTC 
Subversion's svnserve server process may exit when a client sends certain sequences of protocol commands. This can lead to disruption for users of the server. A null-pointer-dereference in svnserve results in a remote unauthenticated Denial-of-Service in some server configurations. The vulnerability can be triggered by an unauthenticated user if the server is configured with anonymous access enabled.

The problem originates in opening a new connection to svnserve. On failure to find the specified repository or to be authorized to access it, svnserve logs and reports the error, but also keeps the connection open despite its incomplete initialization. If the client sends any further command on the same connection, then a null-pointer dereference occurs in svnserve.

Exploitation results in denial of service by crashing an svnserve process. The impact of this differs depending on how svnserve is launched, including the different run modes selected by options such as "svnserve -d", "svnserve -T -d", "svnserve -t", and "svnserve -i".
Comment 9 Marian Rehak 2019-08-01 06:17:16 UTC 
Created subversion tracking bugs for this issue:

Affects: fedora-all [bug 1735579]
Comment 13 Huzaifa S. Sidhpurwala 2019-08-06 03:52:17 UTC 
External References:

https://subversion.apache.org/security/CVE-2019-0203-advisory.txt
Comment 19 errata-xmlrpc 2019-08-15 17:48:34 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2019:2512 https://access.redhat.com/errata/RHSA-2019:2512
Comment 20 Product Security DevOps Team 2019-08-15 20:47:01 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2019-0203
Comment 22 msiddiqu 2019-08-16 05:50:59 UTC 
Acknowledgments:

Name: the Subversion project (Apache Software Foundation)
Upstream: Tomas Bortoli