Sophos SG UTM Remote Code Execution Vulnerability (CVE-2020-25223)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
A remote code execution vulnerability exists in the WebAdmin of Sophos SG UTM before v9.705 MR5, v9.607 MR7, and v9.511 MR11
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.
Conflicting version data — version display is hidden until the data is resolved.
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Metrics
9.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
9.8
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: CVE.org
96.8 %
EPSS score
High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
Source: FIRST EPSS, percentile 99.89
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- 228.82 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 exploited
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- 9.8 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- 9.8
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- 96.8 %
- High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
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- 99.89
- 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 · automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 3 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-78
Response and mitigation
Why act now?
Prioritisation rationale
This CVE is on KEV because the vulnerable component (WebAdmin) is reachable over the network without authentication and yields direct code execution on a perimeter security appliance — the classic internet-to-internal pivot. Attackers routinely abuse UTM and VPN-gateway flaws of this class for initial access, credential harvesting (local users, LDAP binds) and lateral movement into internal zones; the exploitation likelihood sits among the highest in the KEV catalogue. For NIS2-scoped organisations running SG UTM at the edge this is a P1 case: patch or take offline, overriding change-freeze windows, and perform a compromise assessment on any appliance that had WebAdmin internet-exposed before the fix was applied.
Runbook step 1
Immediate response (0-24 h)
- Upgrade Sophos SG UTM to a fixed release: v9.705 MR5, v9.607 MR7 or v9.511 MR11. Deploy the Up2Date package via WebAdmin or the console (
auisys.plx) and schedule the appliance reboot. - Remove WebAdmin (default TCP 4444) from any internet-facing exposure immediately: disable the "WAN → Any:4444" rule or restrict it via packet filter to dedicated admin jump hosts. Verify that User Portal (TCP 443) does not inadvertently expose WebAdmin.
- Rotate all local UTM admin accounts and API tokens; re-bind RADIUS/LDAP service accounts, since a WebAdmin RCE could have harvested credentials.
- Export the configuration (
.abf), diff against the last known-good baseline and look for unexpected users, shell accounts, backup jobs or cron entries under/var/mdw/. - If patching cannot happen within 24 h: take the appliance off the internet during a maintenance window, or front it with a reverse proxy enforcing client certificates for WebAdmin.
- Upgrade Sophos SG UTM to a fixed release: v9.705 MR5, v9.607 MR7 or v9.511 MR11. Deploy the Up2Date package via WebAdmin or the console (
Runbook step 2
Mitigation layers
- Network segmentation: expose WebAdmin only from a dedicated management VLAN; ACL on the core switch to allow TCP 4444, SSH (22) and User Portal exclusively from the admin subnet.
- Mandatory VPN for administration: force all UTM management access through IPsec/SSL VPN with MFA, including vendor support (enable Sophos "Remote Assistance" only ad-hoc, disable afterwards).
- Egress filtering on the UTM itself: block outbound connections initiated by the appliance toward reverse-shell ports, IRC or unusual HTTPS destinations; whitelist only Sophos update servers and required resolvers.
- Upstream WAF/reverse proxy with rules that block requests to
/webadmin/,/var/,/nuser/and POST bodies containing Perl/shell metacharacters (;,`,$() on WebAdmin paths. - IAM hardening: enforce role separation in WebAdmin, reduce the number of SuperAdmin accounts, enable login throttling and account lockout, set session timeout to ≤ 15 min.
- Centralise logging: ship UTM syslog (CEF/syslog over TLS) to the SIEM so appliance logs survive a local wipe post-compromise.
Runbook step 3
Detection rules
- Parse UTM web access logs (
/var/log/httpd/access.logand WebAdmin logs) for POST requests against WebAdmin endpoints with unusually large bodies or shell metacharacters. Sigma shape:selection: cs-method: POST AND cs-uri-stem|contains: '/webadmin/' AND cs-uri-query|re: '[;$|]'`. - Process telemetry on the UTM (confd/httpd child processes): alert on unexpected children such as
/bin/sh,perl -e,wget,curl,nc— any shell execution descending from the WebAdmin daemon is suspicious. - Netflow/Zeek: outbound connections from the UTM management IP to non-Sophos destinations, in particular short-lived TCP sessions to hosting providers or Tor exits. KQL shape:
NetworkEvents | where SrcIp == "<utm_ip>" and DstPort !in (53,80,443) and DstAsn !~ "Sophos". - File integrity check: diff
/var/confd/,/var/mdw/and/home/login/against a baseline; alert on new SUID binaries or modified cron entries. - Authentication monitoring: inspect
aua.logfor successful WebAdmin logins outside admin hours or from unknown source IPs; enable vendor-published detection content in Sophos XDR where licensed.
- Parse UTM web access logs (
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 remote code execution vulnerability exists in the WebAdmin of Sophos SG UTM before v9.705 MR5, v9.607 MR7, and v9.511 MR11
Source: NVD (NIST), cvelistv5, CISA KEV Catalog
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| sophos | unified_threat_management |
|
|
Vendors and products
Weakness classes (CWE)
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Base
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
Entry at MITRE CWE-78
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 | |
| Packet Storm | Sophos UTM WebAdmin SID Command Injection (opens in a new tab)packetstormsecurity.com | PoC (publicly reported)reported, not verified | — |
References & sources
- cwe.mitre.orgdata/definitions/78.htmlTechnical description
- community.sophos.comb/security-blogNot applicable, Vendor advisory
- community.sophos.comb/security-blog/posts/advisory-resolved-rce-in-sg-utm-webadmin-…Vendor advisory
- packetstormsecurity.comfiles/164697/Sophos-UTM-WebAdmin-SID-Command-Injection.htmlExploit, Third-party advisory, Vulnerability database
- secpod.comblog/remote-code-execution-in-sophos-utmExploit, Third-party advisory
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2020-25223government-resource, US government resource
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<a href="https://intel.neosec.eu/en/cve/CVE-2020-25223"><img src="https://intel.neosec.eu/badge/cve/CVE-2020-25223.svg?lang=en" alt="CVE-2020-25223 – NEOSEC Intel" height="20"></a>