Security readout for executives and security teams
Plain-English summary
Apport, Canonical's crash-reporting tool, could create or use a root-owned, world-writable lock file in a location a local user may influence. On affected Ubuntu packages, this can let a logged-in attacker tamper with where the lock file is placed and potentially gain higher privileges.
Executive priority
Treat this as a moderate-priority Linux hardening and patching item. It is not remotely exploitable based on supplied evidence, but it can matter on shared systems because a local foothold could become administrative control.
Technical view
CVE-2020-8831 is a local privilege-escalation issue in Apport involving insecure temporary lock-file handling under /var/lock/apport, a world-writable tmpfs path. If the apport directory is missing or attacker-controlled, a symlink can redirect the root-owned lock file. The issue is classified as CWE-379 with CVSS 3.1 score 6.5.
Likely exposure
Exposure is most relevant to Ubuntu systems running affected Canonical Apport versions 2.20.1, 2.20.9, or 2.20.11 before the fixed package releases listed by Ubuntu. Risk is higher on shared servers, developer workstations, or environments where untrusted users have local accounts.
Exploitation context
The CVE is not listed as KEV in the supplied bundle, and no cited source states active exploitation. The attack requires local privileges but has low attack complexity and no user interaction, with potential high integrity impact through privilege escalation.
Researcher notes
The key condition is unsafe creation or reuse of /var/lock/apport state in a world-writable tmpfs area. Validation should focus on package version, local-user exposure, and whether vendor patches from the Ubuntu security notices are present. Do not assume exploitation without additional evidence.
Mitigation direction
- Update Apport to the fixed Ubuntu package version for the installed release.
- Apply Ubuntu guidance from USN-4315-1 and USN-4315-2.
- Prioritize shared or multi-user Linux systems where local users are less trusted.
- If patch status is unclear, verify current vendor guidance before relying on compensating controls.
Validation and detection
- Inventory Ubuntu hosts with Apport installed and identify installed package versions.
- Compare package versions against the fixed releases named in the CVE description.
- Check whether systems allow local access by non-administrative or untrusted users.
- Review security monitoring for suspicious local privilege-escalation activity around Apport.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-379: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-8831 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N24Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://launchpad.net/bugs/1862348CVE reference · x_refsource_CONFIRM
- https://usn.ubuntu.com/4315-1/CVE reference · x_refsource_CONFIRM
- USN-4315-2CVE reference · vendor-advisory, x_refsource_UBUNTU
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Creation of Temporary File in Directory with Insecure Permissions
Creation of Temporary File in Directory with Insecure Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.