CVE-2021-36798

Cobalt Strike vulnerability

CVSS

7.5

EPSS

4.3%

EPSS pct

90th

Exploited

No known

A Denial-of-Service (DoS) vulnerability was discovered in Team Server in HelpSystems Cobalt Strike 4.2 and 4.3. It allows remote attackers to crash the C2 server thread and block beacons' communication with it.

Affected vendor

Helpsystems

Affected product

Cobalt Strike

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness type (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

Published

2021-08-09

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to availability.

Its EPSS score of 4.3% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 90% of all scored CVEs.

Check your external exposure to CVE-2021-36798

Confirm whether Helpsystems Cobalt Strike is running on any internet-facing host or subdomain.
Match discovered service fingerprints against the version affected by CVE-2021-36798.
Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-36798

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2021-36798 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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