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attackerkbAttackerKBAKB:B2EBBF0E-24E2-4432-8E53-7E8A540D8917
HistoryMar 17, 2020 - 12:00 a.m.

Installing a malicious gem may lead to arbitrary code execution

2020-03-1700:00:00
attackerkb.com
12

8.8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

6.8 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:P/I:P/A:P

An issue was discovered in RubyGems 2.6 and later through 3.0.2. A crafted gem with a multi-line name is not handled correctly. Therefore, an attacker could inject arbitrary code to the stub line of gemspec, which is eval-ed by code in ensure_loadable_spec during the preinstall check.

Recent assessments:

busterb at May 09, 2019 5:57pm UTC reported:

Rubygems has a vulnerability that allows for arbitrary code execution while a gem is being installed. However, it’s unclear how this is any worse than either using the malicious gem itself, or using the ability of gems to compile and execute arbitrary build instructions in the first place. It is interesting to be able to name a gem a particular way to create code execution. But you have to convince someone to install your gem in the first place. I presume that rubygems.org now prevents malicious gems from being published, but it would be interesting to see.

0xEmma at March 15, 2020 7:14pm UTC reported:

Rubygems has a vulnerability that allows for arbitrary code execution while a gem is being installed. However, it’s unclear how this is any worse than either using the malicious gem itself, or using the ability of gems to compile and execute arbitrary build instructions in the first place. It is interesting to be able to name a gem a particular way to create code execution. But you have to convince someone to install your gem in the first place. I presume that rubygems.org now prevents malicious gems from being published, but it would be interesting to see.

avishwakarma-r7 at March 17, 2020 5:28am UTC reported:

Rubygems has a vulnerability that allows for arbitrary code execution while a gem is being installed. However, it’s unclear how this is any worse than either using the malicious gem itself, or using the ability of gems to compile and execute arbitrary build instructions in the first place. It is interesting to be able to name a gem a particular way to create code execution. But you have to convince someone to install your gem in the first place. I presume that rubygems.org now prevents malicious gems from being published, but it would be interesting to see.

Assessed Attacker Value: 1
Assessed Attacker Value: 1Assessed Attacker Value: 3

8.8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

6.8 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:P/I:P/A:P