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MediumCISA KEVExploited in the wildPublic exploit

Arbitrary File Read in SonicWall Email Security 10.0.9.x

IdentifiersCVE-2021-20023CWE-552

SonicWall Email Security (ES) 10.0.9.x contains a post-authentication arbitrary file read vulnerability that allows an authenticated attacker to read arbitrary files from the remote host. The provided content explicitly states that a post-authenticated attacker can read an arbitrary file on the remote host, and Mandiant’s reporting places this issue among the SonicWall ES flaws disclosed in April 2021. No specific vulnerable function, endpoint, or code path is identified in the provided material.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an authenticated attacker to access arbitrary files on the SonicWall Email Security host. Depending on file selection, this can expose sensitive application data, configuration files, credentials, account information, logs, and other locally stored information, which may facilitate further compromise, privilege escalation, persistence, or lateral movement. The exact scope of accessible files is not further specified in the provided content.

Mitigation

If you can’t patch tonight, do this now.

Apply the vendor-provided fixed version as the primary mitigation. Until patching is completed, reduce exposure by limiting access to SonicWall ES administrative and authenticated interfaces to trusted networks and accounts only, reviewing Tomcat and SonicWall ES logs for suspicious authenticated requests, monitoring for web shells and abnormal child processes of the Tomcat service, and reviewing sensitive configuration/account files for unauthorized access or follow-on compromise. The content does not provide a CVE-2021-20023-specific workaround beyond upgrading.

Remediation

Patch, then assume compromise.

Upgrade SonicWall Email Security to a fixed release. The provided content states that SonicWall and Mandiant recommended upgrading to version 10.0.9.6173 for Windows deployments or 10.0.9.6177 for Hardware and ESXi deployments to mitigate CVE-2021-20021, CVE-2021-20022, and CVE-2021-20023. SonicWall Hosted Email Security (HES) customers were automatically updated and required no action.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
SonicwallEmail Securityapplication
SonicwallEmail Security Appliance 3300 Firmwareoperating_system
SonicwallEmail Security Appliance 4300 Firmwareoperating_system
SonicwallEmail Security Appliance 5000 Firmwareoperating_system
SonicwallEmail Security Appliance 5050 Firmwareoperating_system
SonicwallEmail Security Appliance 7000 Firmwareoperating_system
SonicwallEmail Security Appliance 7050 Firmwareoperating_system
SonicwallEmail Security Appliance 8300 Firmwareoperating_system
SonicwallEmail Security Appliance 9000 Firmwareoperating_system
SonicwallEmail Security Virtual Applianceapplication
SonicwallHosted Email Securityapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware1

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.