CVE-1999-0016
CVE-1999-0016 is a security vulnerability in cisco ios. 5 public exploit references exist, so weaponization risk is real. O3 Security detects and blocks CVE-1999-0016 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
Land IP denial of service.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
Land IP denial of service.
Affected Products
iosciscoinetgnuhp-uxhpwindows 95microsoftwindows ntmicrosoftwinsockmicrosoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 / NetBSD 1 - 'land.c' loopback Denial of Service (1)
by m3lt · Nov 20, 1997
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 / NetBSD 1 - 'land.c' loopback Denial of Service (4)
by MondoMan · Nov 20, 1997
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 / NetBSD 1 - 'land.c' loopback Denial of Service (3)
by m3lt · Nov 20, 1997
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 / NetBSD 1 - 'land.c' loopback Denial of Service (5)
by Dejan Levaja · Nov 20, 1997
FreeBSD 2.x / HP-UX 9/10/11 / Kernel 2.0.3 / Windows NT 4.0/Server 2003 / NetBSD 1 - 'land.c' loopback Denial of Service (2)
by Konrad Malewski · Nov 20, 1997
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every cisco ios deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-1999-0016 yet — track the cisco ios advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-1999-0016 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-1999-0016. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-1999-0016 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-1999-0016 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.