Bug 894407 (CVE-2013-0176)

Summary: CVE-2013-0176 libssh: NULL dereference leads to denial of service
Product: [Other] Security Response Reporter: Vincent Danen <vdanen>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED CURRENTRELEASE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: asn, security-response-team
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=moderate,public=20130122,reported=20130109,source=redhat,cvss2=5.0/AV:N/AC:L/Au:N/C:N/I:N/A:P,fedora-all/libssh=affected,cwe=CWE-476[auto]
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2013-02-05 16:56:56 EST Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Bug Depends On: 902992    
Bug Blocks:    
Attachments:
Description Flags
Patch for CVE-2013-0176 none

Description Vincent Danen 2013-01-11 11:44:18 EST
A NULL dereference was found in libssh 0.5.3's publickey_from_privatekey() function.  When a server using libssh receives a "Client: Key Exchange Init", the server sets up the session and tries to set the algorithms by matching what the user specified vs what is supported in crypt_set_algorithms_server().  If there is no match, it will lead to a NULL dereference when receiving the "Client: Diffie-Hellman Key Exchange Init" packet, which will cause the program using libssh to crash.
Comment 2 Andreas Schneider 2013-01-14 08:40:17 EST
Created attachment 678235 [details]
Patch for CVE-2013-0176
Comment 5 Andreas Schneider 2013-01-22 10:24:57 EST
Fedora bugs are created automatically?
Comment 6 Vincent Danen 2013-01-22 16:40:33 EST
Created libssh tracking bugs for this issue

Affects: fedora-all [bug 902992]
Comment 7 Vincent Danen 2013-01-22 16:40:59 EST
Sorry, no, I forgot about the time.  =(
Comment 8 Fedora Update System 2013-02-01 23:19:45 EST
libssh-0.5.4-1.fc17 has been pushed to the Fedora 17 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 9 Fedora Update System 2013-02-01 23:28:16 EST
libssh-0.5.4-1.fc18 has been pushed to the Fedora 18 stable repository.  If problems still persist, please make note of it in this bug report.