Bug 1749181 (CVE-2017-18594)

Summary: CVE-2017-18594 nmap: denial of service condition due to a double free when SSH connection fails
Product: [Other] Security Response Reporter: Dhananjay Arunesh <darunesh>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: mhlavink, pzhukov
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: nmap 7.80 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2019-10-16 10:10:33 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: 1700114, 1749182    
Bug Blocks: 1749184    

Description Dhananjay Arunesh 2019-09-05 05:49:50 UTC
A vulnerability was found in nse_libssh2.cc in Nmap 7.70 is subject to a denial of service condition due to a double free when an SSH connection fails, as demonstrated by a leading \n character to ssh-brute.nse or ssh-auth-methods.nse.

Reference:
https://github.com/nmap/nmap/issues/1227
https://github.com/nmap/nmap/issues/1077
https://seclists.org/nmap-dev/2018/q2/45
https://github.com/AMatchandaHaystack/Research/blob/master/Nmap%26libsshDF
https://github.com/nmap/nmap/commit/350bbe0597d37ad67abe5fef8fba984707b4e9ad
https://seclists.org/nmap-announce/2019/0

Comment 1 Dhananjay Arunesh 2019-09-05 05:50:21 UTC
Created nmap tracking bugs for this issue:

Affects: fedora-all [bug 1749182]

Comment 2 Cedric Buissart 2019-10-16 10:10:05 UTC
Statement:

Red Hat Enterprise Linux 8 is shipped with a vulnerable version of nmap sources, however, the libssh2 module is explicitly excluded from compilation, and is thus not affected. A future update may fix the source.

Red Hat Enterprise Linux 7 and older are shipped with nmap-6.40 and older, which do not contain the libssh2 module.