Background exploitation KEV catalog No authentication

CVE-2021-35247

SolarWinds Serv-U Improper Input Validation Vulnerability

CheckOps priority index

3.6/10 Patch within 7 days

Severity4.3

Probability0.4

Exploitation3/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 3.7% +0.2 pts in 7 days

CVSS 3.1 4.3 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:

Exploited for 1,747 days 21 Jan 2022

CISA due date 04 Feb 2022 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 3 / 5

KEV catalog (CISA)21 Jan 2022
Exploited in EUVD (ENISA)21 Jan 2022
Used by ransomwareno
EPSS above 10 %3.7%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

Serv-U web login screen to LDAP authentication was allowing characters that were not sufficiently sanitized. SolarWinds has updated the input mechanism to perform additional validation and sanitization. Please Note: No downstream affect has been detected as the LDAP servers ignored improper characters. To insure proper input validation is completed in all environments. SolarWinds recommends scheduling an update to the latest version of Serv-U.

Affected products

Serv-U

Affected versions

15.2.5 and previous versions <15.3

Weaknesses (CWE)

CWE-20

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

07 Jan 2022
Published
21 Jan 2022
Exploitation reported (ENISA)
21 Jan 2022
Added to the KEV catalog
04 Feb 2022
CISA remediation due date

References

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