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CVE-2020-8831

MEDIUMCVSS 5.5/10EPSS 0.66%

Last modified

CVE-2020-8831 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. EPSS estimates a 0.66% chance of exploitation in the next 30 days.

Description

Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. This allows for a symlink attack if an attacker were to create a symlink at /var/lock/apport, changing apport's lock file location. This file could then be used to escalate privileges, for example. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS Probability
0.66%

46.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CanonicalUbuntu Linux14.04
CanonicalUbuntu Linux16.04
CanonicalUbuntu Linux18.04
CanonicalUbuntu Linux19.10
Apport ProjectApportAll versions

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2020-8831?
Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. This allows for a symlink attack if an attacker were to create a symlink at /var/lock/apport, changing apport's lock file location. This file could then be used to escalate privileges, for example. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.
How severe is CVE-2020-8831?
CVE-2020-8831 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.66% probability of exploitation in the next 30 days.
How do I fix CVE-2020-8831?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-8831?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST