Vulnerability Name:

CVE-2020-11934 (CCN-186052)

Assigned:2020-05-22
Published:2020-05-22
Updated:2020-08-05
Summary:It was discovered that snapctl user-open allowed altering the $XDG_DATA_DIRS environment variable when calling the system xdg-open. OpenURL() in usersession/userd/launcher.go would alter $XDG_DATA_DIRS to append a path to a directory controlled by the calling snap. A malicious snap could exploit this to bypass intended access restrictions to control how the host system xdg-open script opens the URL and, for example, execute a script shipped with the snap without confinement. This issue did not affect Ubuntu Core systems. Fixed in snapd versions 2.45.1ubuntu0.2, 2.45.1+18.04.2 and 2.45.1+20.04.2.
CVSS v3 Severity:5.9 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N)
5.2 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): High
Availibility (A): None
5.9 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N)
5.2 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): High
Availibility (A): None
CVSS v2 Severity:1.9 Low (CVSS v2 Vector: AV:L/AC:M/Au:N/C:N/I:P/A:N)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): Partial
Availibility (A): None
4.6 Medium (CCN CVSS v2 Vector: AV:L/AC:L/Au:S/C:N/I:C/A:N)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): None
Integrity (I): Complete
Availibility (A): None
Vulnerability Type:CWE-668
Vulnerability Consequences:Bypass Security
References:Source: MITRE
Type: CNA
CVE-2020-11934

Source: CCN
Type: Launchpad Bug #1880085
snap userd's OpenURL method allows sandox escape

Source: XF
Type: UNKNOWN
snapd-cve202011934-sec-bypass(186052)

Source: CCN
Type: snapd GIT Repository
snapd

Source: CONFIRM
Type: Third Party Advisory
https://launchpad.net/bugs/1880085

Source: CONFIRM
Type: Vendor Advisory
https://ubuntu.com/USN-4424-1

Vulnerable Configuration:Configuration 1:
  • cpe:/o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*

    • * Denotes that component is vulnerable
    BACK
    canonical ubuntu linux 16.04
    canonical ubuntu linux 18.04
    canonical ubuntu linux 19.10
    canonical ubuntu linux 20.04