CVE Vulnerabilities

CVE-2017-7500

Improper Link Resolution Before File Access ('Link Following')

Published: Aug 13, 2018 | Modified: Oct 09, 2019
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
7.3 MODERATE
CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Ubuntu
LOW

It was found that rpm did not properly handle RPM installations when a destination path was a symbolic link to a directory, possibly changing ownership and permissions of an arbitrary directory, and RPM files being placed in an arbitrary destination. An attacker, with write access to a directory in which a subdirectory will be installed, could redirect that directory to an arbitrary location and gain root privilege.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Name Vendor Start Version End Version
Rpm Rpm 4.13.0.0 (including) 4.13.0.2 (excluding)
Rpm Rpm 4.14.0.0-rc1 (including) 4.14.0.0-rc1 (including)
Rpm Rpm 4.14.0.0-rc2 (including) 4.14.0.0-rc2 (including)
Rpm Ubuntu artful *
Rpm Ubuntu cosmic *
Rpm Ubuntu disco *
Rpm Ubuntu eoan *
Rpm Ubuntu esm-apps/xenial *
Rpm Ubuntu esm-infra-legacy/trusty *
Rpm Ubuntu precise/esm *
Rpm Ubuntu trusty *
Rpm Ubuntu trusty/esm *
Rpm Ubuntu upstream *
Rpm Ubuntu xenial *
Rpm Ubuntu yakkety *
Rpm Ubuntu zesty *

Potential Mitigations

  • Follow the principle of least privilege when assigning access rights to entities in a software system.
  • Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References