Zoho ManageEngine ADSelfService Plus Authentication Bypass
CVE-2021-40539 is a critical-severity use of incorrectly-resolved name or reference vulnerability in Manageengine Adselfservice Plus from Zoho, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 6.1 as the first without the flaw, so updating Manageengine Adselfservice Plus to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild, including in ransomware campaigns.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Manageengine Adselfservice Plus to 6.1 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on manageengine.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Zoho | Manageengine Adselfservice Plus | before 6.1; 6.1 | 6.1 |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 3.1 | 9.8 | Critical | CISA (ADP) |
| CVSS 2.0 | 7.5 | High | NVD |
Official description
Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Incorrectly-Resolved Name or Reference
The product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere.
More Use of Incorrectly-Resolved Name or Reference vulnerabilities (CWE-706)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40539US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/165085/ManageEngine-ADSelfService-Plus-Authentication-Bypass-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
Other references
- manageengine.comProduct
Other vulnerabilities in Manageengine Adselfservice Plus
- 9.0 Critical severity
- 8.4 High severity
- 8.1 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Use of Incorrectly-Resolved Name or Reference vulnerabilities
- 9.8 Critical severity
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