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CVE-2020-5811: Authenticated path traversal in Umbraco CMS

6.5

CVSS Score
3.1

Basic Information

EPSS Score
0.84892%
Published
4/13/2021
Updated
2/1/2023
KEV Status
No
Technology
TechnologyC#

Technical Details

CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Package NameEcosystemVulnerable VersionsFirst Patched Version
UmbracoCmsnuget< 8.9.28.9.2

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability stems from improper path validation during package installation. Key functions identified are:

  1. PackageController.InstallPackage - Entry point for package installation that would process malicious package.xml
  2. PackageInstallation.ExtractPackageFiles - Directly handles file extraction logic where path traversal would occur While exact code isn't shown, advisory explicitly states the install process lacked the path containment checks present in uninstall routines. These functions would appear in stack traces when processing malicious package files with '../' in orgPath attributes.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

*n *ut**nti**t** p*t* tr*v*rs*l vuln*r**ility *xists *urin* p**k*** inst*ll*tion in Um*r**o *MS <= *.*.* or *urr*nt, w*i** *oul* r*sult in *r*itr*ry *il*s **in* writt*n outsi** o* t** sit* *om* *n* *xp**t** p*t*s w**n inst*llin* *n Um*r**o p**k***.

Reasoning

T** vuln*r**ility st*ms *rom improp*r p*t* v*li**tion *urin* p**k*** inst*ll*tion. K*y *un*tions i**nti*i** *r*: *. P**k****ontroll*r.Inst*llP**k*** - *ntry point *or p**k*** inst*ll*tion t**t woul* pro**ss m*li*ious p**k***.xml *. P**k***Inst*ll*tio