Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.48% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2021
CVE-2020-36167High confidence
On Windows systems, this path could translate to <drive>:\usr\local\ssl\openssl.cnf
Unknown · Unknown
9.3CriticalCVSS 3.1
Within 7 days
Fix not verifiedCritical technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Compensating controls
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified01
What, why and how
An issue was discovered in the server in Veritas Backup Exec through 16.2, 20.6 before hotfix 298543, and 21.1 before hotfix 657517. On start-up, it loads the OpenSSL library from the Installation folder. This library in turn attempts to load the /usr/local/ssl/openssl.cnf configuration file, which may not exist. On Windows systems, this path could translate to <drive>:\usr\local\ssl\openssl.cnf. A low privileged user can create a :\usr\local\ssl\openssl.cnf configuration file to load a malicious OpenSSL engine, resulting in arbitrary code execution as SYSTEM when the service starts. This gives the attacker administrator access on the system, allowing the attacker (by default) to access all data, access all installed applications, etc. If the system is also an Active Directory domain controller, then this can affect the entire domain.
What
An issue was discovered in the server in Veritas Backup Exec through 16.2, 20.6 before hotfix 298543, and 21.1 before hotfix 657517. On start-up, it loads the OpenSSL library from the Installation folder. This library in turn attempts to load the /usr/local/ssl/openssl.cnf configuration file, which may not exist. On Windows systems, this path could translate to <drive>:\usr\local\ssl\openssl.cnf. A low privileged user can create a :\usr\local\ssl\openssl.cnf configuration file to load a malicious OpenSSL engine, resulting in arbitrary code execution as SYSTEM when the service starts. This gives the attacker administrator access on the system, allowing the attacker (by default) to access all data, access all installed applications, etc. If the system is also an Active Directory domain controller, then this can affect the entire domain.
Why
The upload path does not sufficiently restrict the type, name, location or later execution of attacker-supplied files.
How
An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.
What
An issue was discovered in the server in Veritas Backup Exec through 16.2, 20.6 before hotfix 298543, and 21.1 before hotfix 657517. On start-up, it loads the OpenSSL library from the Installation folder. This library in turn attempts to load the /usr/local/ssl/openssl.cnf configuration file, which may not exist. On Windows systems, this path could translate to <drive>:\usr\local\ssl\openssl.cnf. A low privileged user can create a :\usr\local\ssl\openssl.cnf configuration file to load a malicious OpenSSL engine, resulting in arbitrary code execution as SYSTEM when the service starts. This gives the attacker administrator access on the system, allowing the attacker (by default) to access all data, access all installed applications, etc. If the system is also an Active Directory domain controller, then this can affect the entire domain.
Why
The upload path does not sufficiently restrict the type, name, location or later execution of attacker-supplied files.
How
An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- local access → Unrestricted Upload of File with Dangerous Type → execute code or commands in the affected security context
- Attack surface
- Local
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-434 ↗
CWE-434: Unrestricted Upload of File with Dangerous Type. The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AC:L/AV:L/A:H/C:H/I:H/PR:N/S:C/UI:NCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.AVLocalAttack vector: The attacker needs local access to the vulnerable system.AHighAvailability impact: A successful attack can cause a major loss.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.PRNonePrivileges required: The attacker does not need an account or existing privileges.SChangedScope: The attack can affect a component governed by a different security authority.UINoneUser interaction: No action by another user is required.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix not verified
- Affected
- n/a
- Fixed
- No fixed version is explicitly recorded in the structured CVE data.
- Action
- No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 6 Jan 2021 · Last source change 4 Aug 2024, 17:23 UTC · CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2020-23745
Product sourceUnavailable
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.