CVE-2016-7407 Dropbear SSH Project CVE debrief

Who should care

Administrators and integrators who deploy Dropbear SSH, especially systems that include or expose the dropbearconvert utility, should prioritize this issue. It is most relevant anywhere untrusted OpenSSH key files may be processed, including embedded, appliance, and server environments that rely on Dropbear SSH versions before 2016.74.

Technical summary

The vulnerability is described as an arbitrary code execution issue in the dropbearconvert command when handling a crafted OpenSSH key file. NVD classifies the weakness as CWE-20 (Improper Input Validation). The affected version range in the NVD CPE data ends at 2016.73, with 2016.74 indicated as the fixed release boundary in the description.

Defensive priority

Critical. The combination of network attack vector, no privileges, no user interaction, and high confidentiality/integrity/availability impact warrants urgent patching or mitigation wherever Dropbear SSH is present.

Recommended defensive actions

• Upgrade Dropbear SSH to 2016.74 or later, based on the NVD affected-version boundary.
• Inventory systems that ship or bundle Dropbear SSH and verify whether dropbearconvert is installed or used.
• Restrict or remove workflows that accept untrusted OpenSSH key files until remediation is complete.
• Apply vendor or distribution advisories and patches referenced in the corpus, including the Dropbear patch link and Gentoo GLSA.
• If immediate upgrading is not possible, isolate affected hosts and limit exposure of any key-conversion workflows to trusted administrators only.
• Validate that downstream packages or firmware images have incorporated the fixed Dropbear release, not just the upstream source code.

Evidence notes

This debrief is based on the supplied NVD record and its linked references. The description explicitly states that dropbearconvert in Dropbear SSH before 2016.74 can execute arbitrary code via a crafted OpenSSH key file. The NVD CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) and CWE-20 classification support the severity and defensive urgency. The corpus also lists a version boundary of 2016.73 and references a patch, a mailing list post, and a Gentoo advisory.

Official resources