UBUNTU-CVE-2015-3246: High severity ubuntu/libuser vulnerability

Q: What access does an attacker need to exploit this issue?

The issue is locally exploitable: an attacker needs the ability to run as a local user. No privileges or user interaction are required, but exploitation requires causing an error while userhelper modifies /etc/passwd.

Q: What is the direct impact if exploitation succeeds?

A local attacker can cause /etc/passwd to be left in an inconsistent state, resulting in denial of service. The issue can also be combined with CVE-2015-3245 to gain privileges.

Q: Which libuser versions are affected?

Affected versions are libuser before 0.56.13-8 and versions in the 0.60 series before 0.60-7, where libuser is used by userhelper in the usermode package.

Published Aug 11, 2015

Updated

libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package, directly modifies /etc/passwd, which allows local users to cause a denial of service (inconsistent file state) by causing an error during the modification. NOTE: this issue can be combined with CVE-2015-3245 to gain privileges.

Affected Software

3 affected componentsFixes available

ubuntu/libuser<1:0.56.9.dfsg.1-1.2ubuntu2+esm1

1:0.56.9.dfsg.1-1.2ubuntu2+esm1

ubuntu/libuser*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/libuser to a version that resolves this vulnerability.
Fixed in 1:0.56.9.dfsg.1-1.2ubuntu2+esm1

Event History

Aug 11, 2015

CVE Published

via OSV·02:59 PM

Data Sourced

via OSV·02:59 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

What access does an attacker need to exploit this issue?

The issue is locally exploitable: an attacker needs the ability to run as a local user. No privileges or user interaction are required, but exploitation requires causing an error while userhelper modifies /etc/passwd.

What is the direct impact if exploitation succeeds?

A local attacker can cause /etc/passwd to be left in an inconsistent state, resulting in denial of service. The issue can also be combined with CVE-2015-3245 to gain privileges.

Which libuser versions are affected?

Affected versions are libuser before 0.56.13-8 and versions in the 0.60 series before 0.60-7, where libuser is used by userhelper in the usermode package.

UBUNTU-CVE-2015-3246: High severity ubuntu/libuser vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

What access does an attacker need to exploit this issue?

What is the direct impact if exploitation succeeds?

Which libuser versions are affected?

Company

Resources

Contact

Frequently Asked Questions

What access does an attacker need to exploit this issue?

What is the direct impact if exploitation succeeds?

Which libuser versions are affected?