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archlinuxArchLinuxASA-201807-9
HistoryJul 16, 2018 - 12:00 a.m.

[ASA-201807-9] libcurl-gnutls: arbitrary code execution

2018-07-1600:00:00
security.archlinux.org
12
arbitrary code execution
libcurl-gnutls
heap memory buffer

CVSS2

7.5

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

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

CVSS3

9.8

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.013

Percentile

86.1%

Arch Linux Security Advisory ASA-201807-9

Severity: High
Date : 2018-07-16
CVE-ID : CVE-2018-0500
Package : libcurl-gnutls
Type : arbitrary code execution
Remote : Yes
Link : https://security.archlinux.org/AVG-734

Summary

The package libcurl-gnutls before version 7.61.0-1 is vulnerable to
arbitrary code execution.

Resolution

Upgrade to 7.61.0-1.

pacman -Syu “libcurl-gnutls>=7.61.0-1”

The problem has been fixed upstream in version 7.61.0.

Workaround

None.

Description

It has been discovered that curl before 7.61.0 might overflow a heap
based memory buffer when sending data over SMTP and using a reduced
read buffer.

When sending data over SMTP, curl allocates a separate “scratch area”
on the heap to be able to escape the uploaded data properly if the
uploaded data contains data that requires it. The size of this
temporary scratch area was mistakenly made to be 2 *
sizeof(download_buffer) when it should have been made 2 *
sizeof(upload_buffer). The upload and the download buffer sizes are
identically sized by default (16KB) but since version 7.54.1, curl can
resize the download buffer into a smaller buffer (as well as larger).
If the download buffer size is set to a value smaller than 10923, the
Curl_smtp_escape_eob() function might overflow the scratch buffer when
sending contents of sufficient size and contents. The curl command line
tool lowers the buffer size when --limit-rate is set to a value smaller
than 16KB.

Impact

A remote attacker is able to execute arbitrary code when sending SMTP
data.

References

https://curl.haxx.se/docs/adv_2018-70a2.html
https://security.archlinux.org/CVE-2018-0500

OSVersionArchitecturePackageVersionFilename
ArchLinuxanyanylibcurl-gnutls< 7.61.0-1UNKNOWN

CVSS2

7.5

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

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

CVSS3

9.8

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.013

Percentile

86.1%