CVE-2021-28024Public exploitNetwork attack vector

Authentication bypass via predictable SSO passwords

Published Nov 8, 2021 · Updated Aug 3, 2024

Authentication bypass in ServiceTonic Helpdesk before 9.0.35937 allows remote attackers to log in without an account password. The SSO login derives a password from SHA-1 over the username, current hour, and a shared low-entropy download code before Base64 encoding and appending _SSOA. Knowledge of a target username and download code is required; successful exploitation grants that user's privileges, including administrator access.

CVSS severity9.8
Critical
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in ServiceTonic Helpdesk before 9.0.35937 allows remote attackers to log in without an account password. The SSO login derives a password from SHA-1 over the username, current hour, and a shared low-entropy download code before Base64 encoding and appending _SSOA. Knowledge of a target username and download code is required; successful exploitation grants that user's privileges, including administrator access.

The record

CVE
CVE-2021-28024
Published
Nov 8, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-330, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-330Use of Insufficiently Random Values
T1078Valid Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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