CVE-2021-35247KEV · OVERDUECWE-20

Improper Input Validation Vulnerability in Serv-U

Medium · published January 7, 2022

Patch now

The score understates this — it's already being exploited

CVSS calls it medium at 4.3. It is confirmed in active exploitation. It sits in the 89.0th percentile for exploit probability.

1723
days past CISA
deadline
CVSS v3.1
4.3
EPSS
3%
Percentile
89.0
In the wild
Confirmed
What it is

⚠️ A sneaky input issue in the Serv-U web login screen could let attackers slip through the cracks if left unchecked! Think of it like a restaurant letting customers order off a menu without checking for food allergies — you might end up serving something dangerous if you don't validate the choices! This vulnerability allows attackers to send poorly sanitized characters during LDAP authentication attempts, potentially causing unexpected behavior. While no serious downstream effects have been detected, it’s still crucial to handle inputs correctly to dodge any surprises and keep your data safe!

Put simply

Think of it like a restaurant letting customers order off a menu without checking for food allergies — you might end up serving something dangerous if you don't validate the choices! CVE-2021-35247 hinges on the Serv-U web login screen allowing ineffective input sanitization for LDAP authentication requests. This oversight could enable malicious characters to be passed through, although the LDAP server itself may ignore them without consequences.

What to do

This vulnerability allows attackers to send poorly sanitized characters during LDAP authentication attempts, potentially causing unexpected behavior. While no serious downstream effects have been detected, it’s still crucial to handle inputs correctly to dodge any surprises and keep your data safe! To safeguard your systems, immediately schedule an update to the latest version of Serv-U where this issue is patched. Ensure that your input validation mechanisms are robust across all environments, even if you’re not experiencing downstream issues right now. You've got this! With some quick action, you’ll have your security squared away in no time! 🛡️

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.03453 · 89.0th percentile
Weakness
CWE-20 · Improper Input Validation
Published
2022-01-07T22:39Z
KEV added
2022-01-21 · due 2022-02-04
EPSS history
Timeline
  • 21 JAN 00:00Z
    Added to CISA KEV — remediate by Feb 4
    kev
  • 07 JAN 22:39Z
    Improper Input Validation Vulnerability in Serv-U
    cvelistv5