Ivanti Pulse Connect Secure Unrestricted File Upload Vulnerability (CVE-2021-22900)
Published In CISA KEV since Sources: SingCERT, CVE.org
- Actively exploited
- Source: ANSSI / CERT-FR How we classify
What is affected, what to do
A vulnerability allowed multiple unrestricted uploads in Pulse Connect Secure before 9.1R11.4 that could lead to an authenticated administrator to perform a file write via a maliciously crafted archive upload in the administrator web interface.
The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.
- Affected
- Pulse Secure Secure
eq Fixed in 9.1R11.4..Fixed in 9.1R11.4
- Pulse Secure Secure
Not sure whether and how you are affected? Ask a question about this vulnerability
Metrics
7.2
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
7.2
CVSS v3
Severity High on the scale from 0 to 10.
Source: SingCERT, CVE.org
14.1 %
EPSS score
Elevated — model estimates 10-50% exploitation likelihood.
Source: FIRST EPSS, percentile 96.6
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 210.62 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- actively exploitedSource: ANSSI / CERT-FR How we classify
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.2 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.2
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 14.1 %
- Elevated — model estimates 10-50% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 96.6
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- Actively exploited
- Published
In CISA KEV since
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- CISA assessment (SSVC)
- Exploitation: active · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 4 February 2025
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-94
Response and mitigation
Why act now?
Prioritisation rationale
This flaw needs high privileges but is network-reachable and requires no user interaction. In the wild, attackers have used it after an authentication bypass or with harvested admin credentials to drop persistent webshells on the VPN appliance itself. Typical targets are government, defence, finance and critical-infrastructure operators, where the SSL VPN is the front door to the internal network. Exploitation likelihood is high, and CISA does not flag known ransomware use. Treat any Pulse/Ivanti Connect Secure build before 9.1R11.4 as top priority. If the admin interface has been internet-facing, assume compromise until integrity checks and log review prove otherwise. Where admin access is tightly segmented and MFA-protected, a scheduled but near-term upgrade window is defensible.
Runbook step 1
Immediate response (0-24 h)
- Upgrade Pulse Connect Secure to 9.1R11.4 or later. Every release before 9.1R11.4 is affected, including all 9.0 builds. Systems on 9.0 need a migration onto the 9.1 train. Consult the vendor advisory for upgrade paths.
- Remove internet exposure of the admin web interface (
/dana-admin/) immediately. Restrict admin access to a dedicated management network or a jump-host allowlist. Use the separate management port where the appliance supports it. - Check appliance integrity. Run the vendor's Integrity Checker Tool (ICT), both the internal and the external scan. Any mismatch indicates tampered system files or webshells. If that happens, treat the box as compromised: factory reset or rebuild it rather than simply patching.
- Rotate all administrator credentials. This covers local admins, AD/LDAP/RADIUS-backed admin roles and the service accounts used for authentication-server binds. Kill active admin sessions. Exploitation requires admin privileges, so stolen credentials or bypass-obtained admin sessions are the realistic entry path.
- Verify the companion flaws are closed. This bug was fixed alongside the authentication bypass CVE-2021-22893 and has been chained with it. Cross-check your build against every Pulse Connect Secure entry on KEV.
- Preserve evidence before remediation. Export the snapshot, admin access logs, event logs and the config backup. For entities in NIS2 scope, start the clock on the 24-hour early-warning obligation to your national CSIRT or authority.
Runbook step 2
Mitigation layers
- Network segmentation: Expose the admin UI only on a management VLAN. Add a perimeter deny rule for
/dana-admin/*from external sources, with explicit exceptions only for named admin source IPs. - WAF/reverse proxy: Block or alert on multipart uploads to
/dana-admin/carrying archive payloads (application/x-tar,application/gzip,application/zip). Also inspect archive member names for traversal sequences (../) or absolute paths. - IAM/least privilege: Keep full-admin accounts to a minimum and use delegated admin roles without import/upload rights. Enforce MFA for admin logins, separate the admin auth realm from the user realm, and shorten session timeouts.
- Configuration and process: Lock down config and package import functions procedurally. Require a change ticket and four-eyes approval for every import.
- Egress control: Limit outbound traffic from the appliance to required destinations (auth servers, NTP, syslog, update endpoints). This hampers webshell callbacks and exfiltration.
- Network segmentation: Expose the admin UI only on a management VLAN. Add a perimeter deny rule for
Runbook step 3
Detection rules
- Appliance admin access log/syslog: Flag successful admin logins from unknown source IPs or outside maintenance windows, then correlate them with any subsequent upload or import action. SPL sketch:
index=pulse sourcetype=pulse:admin (action=login OR "upload" OR "import") | stats values(action) by src_ip, user - Web/proxy logs: Look for POSTs to
/dana-admin/with large bodies and archive content types from non-admin networks. Sigma shape:cs-method: POST AND cs-uri-stem|startswith: '/dana-admin/' AND NOT src_ip|cidr: <admin-net> - Integrity deviations: Alert on any ICT finding of new or modified files. Webshell indicators include unfamiliar scripts reachable under
/dana-na/or/dana/paths with unusual parameters. - Network telemetry (Zeek/Suricata): Watch for new outbound connections from the VPN appliance outside its baseline, such as HTTPS to VPS providers or DNS anomalies. Internal SMB/LDAP/RDP sessions originating from the appliance IP are also suspicious.
- Identity telemetry (AD/IdP): Hunt for Pulse service-account authentications from atypical hosts and for VPN users logging in from implausible geolocations after the suspected compromise window (a sign of credential harvesting). Review Windows Event IDs 4624 and 4625 as well as 4768 and 4769.
- Appliance admin access log/syslog: Flag successful admin logins from unknown source IPs or outside maintenance windows, then correlate them with any subsequent upload or import action. SPL sketch:
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
A vulnerability allowed multiple unrestricted uploads in Pulse Connect Secure before 9.1R11.4 that could lead to an authenticated administrator to perform a file write via a maliciously crafted archive upload in the administrator web interface.
Source: CSA/SingCERT, NVD (NIST), CISA KEV Catalog, cvelistv5
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| — | Pulse Secure Secure |
|
|
| ivanti | connect_secure |
|
|
| pulsesecure | pulse_connect_secure |
|
|
Vendors and products
Weakness classes (CWE)
CWE-94Improper Control of Generation of Code ('Code Injection')
Base
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Entry at MITRE CWE-94
Public exploit references
Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited | |
| ANSSI / CERT-FRLicence Ouverte 2.0, as of | CERTFR-2021-ALE-007 – [MàJ] Vulnérabilité dans Pulse Connect Secure (clôturée 2021-06-21) (opens in a new tab)cert.cyber.gouv.fr | actively exploited |
References & sources
- kb.pulsesecure.netarticles/Pulse_Security_Advisories/SA44784/?kA23Z000000boUWSAYx_refsource_MISC, Broken link, Vendor advisory
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22900government-resource, US government resource
- cert.cyber.gouv.frANSSI / CERT-FR: CERTFR-2021-ALE-007 – [MàJ] Vulnérabilité dans Pulse Connect Secure (clôturée 2021-06-21)cert-fr
Embed badge
Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.
<a href="https://intel.neosec.eu/en/cve/CVE-2021-22900"><img src="https://intel.neosec.eu/badge/cve/CVE-2021-22900.svg?lang=en" alt="CVE-2021-22900 – NEOSEC Intel" height="20"></a>