CVE-2021-0286
Published: 15 July 2021
Summary
CVE-2021-0286 is a high-severity Improper Check or Handling of Exceptional Conditions (CWE-703) vulnerability in Juniper Junos Os Evolved. Its CVSS base score is 7.5 (High).
Operationally, ranked at the 35.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-2905
Vulnerability details
A vulnerability in the handling of exceptional conditions in Juniper Networks Junos OS Evolved (EVO) allows an attacker to send specially crafted packets to the device, causing the Advanced Forwarding Toolkit manager (evo-aftmand-bt or evo-aftmand-zx) process to crash and restart,…
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impacting all traffic going through the FPC, resulting in a Denial of Service (DoS). Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition. Following messages will be logged prior to the crash: Feb 2 10:14:39 fpc0 evo-aftmand-bt[16263]: [Error] Nexthop: Failed to get fwd nexthop for nexthop:32710470974358 label:1089551617 for session:18 probe:35 Feb 2 10:14:39 fpc0 evo-aftmand-bt[16263]: [Error] Nexthop: Failed to get fwd nexthop for nexthop:19241453497049 label:1089551617 for session:18 probe:37 Feb 2 10:14:39 fpc0 evo-aftmand-bt[16263]: [Error] Nexthop: Failed to get fwd nexthop for nexthop:19241453497049 label:1089551617 for session:18 probe:44 Feb 2 10:14:39 fpc0 evo-aftmand-bt[16263]: [Error] Nexthop: Failed to get fwd nexthop for nexthop:32710470974358 label:1089551617 for session:18 probe:47 Feb 2 10:14:39 fpc0 audit[16263]: ANOM_ABEND auid=4294967295 uid=0 gid=0 ses=4294967295 pid=16263 comm="EvoAftManBt-mai" exe="/usr/sbin/evo-aftmand-bt" sig=11 Feb 2 10:14:39 fpc0 kernel: audit: type=1701 audit(1612260879.272:17): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=16263 comm="EvoAftManBt-mai" exe="/usr/sbin/evo-aftmand-bt" sig=1 This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-EVO; 21.1 versions prior to 21.1R2-EVO.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Implements explicit check and handling for the exceptional condition of audit logging process failure.
Provides a defined response to detected conditions by restricting operation, ensuring exceptional conditions are handled rather than ignored or mishandled.
Contingency training equips users with defined procedures to check and respond to exceptional conditions during disruptions, reducing exploitation of mishandled errors.
Performing IR tests ensures exceptional conditions are properly checked and handled to enable effective response.
Testing and evaluation exercises error paths and exceptional conditions, surfacing improper handling that is then remediated through the defined process.
Mandates explicit, predictable handling of exceptional conditions rather than undefined continuation.
Requires systematic prediction and handling of failure conditions, reducing the impact of unhandled exceptional states.
The required verification process supplies the missing checks for exceptional conditions affecting security functions.