Arch Linux Security Advisory ASA-201812-11
==========================================

Severity: High
Date    : 2018-12-18
CVE-ID  : CVE-2018-16873 CVE-2018-16874 CVE-2018-16875
Package : go
Type    : multiple issues
Remote  : Yes
Link    : https://security.archlinux.org/AVG-835

Summary
=======

The package go before version 2:1.11.3-1 is vulnerable to multiple
issues including arbitrary command execution, directory traversal and
denial of service.

Resolution
==========

Upgrade to 2:1.11.3-1.

# pacman -Syu "go>=2:1.11.3-1"

The problems have been fixed upstream in version 1.11.3.

Workaround
==========

None.

Description
===========

- CVE-2018-16873 (arbitrary command execution)

In Go before 1.10.6 and 1.11.x before 1.11.3, the "go get" command is
vulnerable to remote code execution when executed with the -u flag and
the import path of a malicious Go package, or a package that imports it
directly or indirectly. Specifically, it is only vulnerable in GOPATH
mode, but not in module mode (the distinction is documented at
https://golang.org/cmd/go/#hdr-Module_aware_go_get). Using custom
domains, it's possible to arrange things so that a Git repository is
cloned to a folder named ".git" by using a vanity import path that ends
with "/.git". If the Git repository root contains a "HEAD" file, a
"config" file, an "objects" directory, a "refs" directory, with some
work to ensure the proper ordering of operations, "go get -u" can be
tricked into considering the parent directory as a repository root, and
running Git commands on it. That will use the "config" file in the
original Git repository root for its configuration, and if that config
file contains malicious commands, they will execute on the system
running "go get -u".

- CVE-2018-16874 (directory traversal)

In Go before 1.10.6 and 1.11.x before 1.11.3, the "go get" command is
vulnerable to directory traversal when executed with the import path of
a malicious Go package which contains curly braces (both '{' and '}'
characters). Specifically, it is only vulnerable in GOPATH mode, but
not in module mode (the distinction is documented at
https://golang.org/cmd/go/#hdr-Module_aware_go_get). The attacker can
cause an arbitrary filesystem write, which can lead to code execution.

- CVE-2018-16875 (denial of service)

The crypto/x509 package of Go before 1.10.6 and 1.11.x before 1.11.3
does not limit the amount of work performed for each chain
verification, which might allow attackers to craft pathological inputs
leading to a CPU denial of service. Go TLS servers accepting client
certificates and TLS clients are affected.

Impact
======

A remote attacker can execute arbitrary code or perform a denial of
service attack.

References
==========

https://groups.google.com/forum/#!msg/golang-announce/Kw31K8G7Fi0/z2olKn-QCAAJ
https://github.com/golang/go/issues/29230
https://github.com/golang/go/commit/8954addb3294a5e664a9833354bafa58f163fe8f
https://github.com/golang/go/commit/5aedc8af94c0a8ffc58cbd09993192dea9b238db
https://github.com/golang/go/issues/29231
https://github.com/golang/go/commit/90d609ba6156299642d08afc06d85ab770a03972
https://github.com/golang/go/issues/29233
https://github.com/golang/go/commit/df523969435b8945d939c7e2a849b50910ef4c25
https://security.archlinux.org/CVE-2018-16873
https://security.archlinux.org/CVE-2018-16874
https://security.archlinux.org/CVE-2018-16875