CVE-2017-18594 — nse_libssh2

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-08-28T23:50:22.000Z
• Last modified: 2024-08-05T21:28:55.571Z

09References

• seclists.org — https://seclists.org/nmap-dev/2018/q2/45
• github.com — https://github.com/nmap/nmap/issues/1227
• github.com — https://github.com/nmap/nmap/commit/350bbe0597d37ad67abe5fef8fba984707b4e9ad
• github.com — https://github.com/nmap/nmap/issues/1077
• github.com — https://github.com/AMatchandaHaystack/Research/blob/master/Nmap%26libsshDF
• seclists.org — https://seclists.org/nmap-announce/2019/0
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00073.html
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00075.html