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CVE Vulnerabilities

CVE-2016-8622

Heap-based Buffer Overflow

Published: Jul 31, 2018 | Modified: Nov 21, 2024
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.5 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
2.6 LOW
AV:N/AC:H/Au:N/C:N/I:P/A:N
RedHat/V3
3.7 LOW
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Ubuntu
MEDIUM
Additional information
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2016-8622
CWEhttps://cwe.mitre.org/data/definitions/122.html

The URL percent-encoding decode function in libcurl before 7.51.0 is called curl_easy_unescape. Internally, even if this function would be made to allocate a unscape destination buffer larger than 2GB, it would return that new length in a signed 32 bit integer variable, thus the length would get either just truncated or both truncated and turned negative. That could then lead to libcurl writing outside of its heap based buffer.

Weakness

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Software

Name Vendor Start Version End Version
Libcurl Haxx * 7.51.0 (excluding)
Red Hat Software Collections for Red Hat Enterprise Linux 6 RedHat httpd24-curl-0:7.61.1-1.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6 RedHat httpd24-httpd-0:2.4.34-7.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6 RedHat httpd24-nghttp2-0:1.7.1-7.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat httpd24-curl-0:7.61.1-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat httpd24-httpd-0:2.4.34-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat httpd24-nghttp2-0:1.7.1-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS RedHat httpd24-curl-0:7.61.1-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS RedHat httpd24-httpd-0:2.4.34-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS RedHat httpd24-nghttp2-0:1.7.1-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS RedHat httpd24-curl-0:7.61.1-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS RedHat httpd24-httpd-0:2.4.34-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS RedHat httpd24-nghttp2-0:1.7.1-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS RedHat httpd24-curl-0:7.61.1-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS RedHat httpd24-httpd-0:2.4.34-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS RedHat httpd24-nghttp2-0:1.7.1-7.el7 *
Text-Only JBCS RedHat curl *
Curl Ubuntu devel *
Curl Ubuntu precise *
Curl Ubuntu trusty *
Curl Ubuntu upstream *
Curl Ubuntu vivid/stable-phone-overlay *
Curl Ubuntu vivid/ubuntu-core *
Curl Ubuntu xenial *
Curl Ubuntu yakkety *
Curl Ubuntu zesty *

Potential Mitigations

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
  • D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
  • Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
  • Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
  • For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

References

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