CVE Vulnerabilities

CVE-2020-1916

Heap-based Buffer Overflow

Published: Mar 10, 2021 | Modified: Nov 21, 2024
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/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
RedHat/V3
Ubuntu
MEDIUM

An incorrect size calculation in ldap_escape may lead to an integer overflow when overly long input is passed in, resulting in an out-of-bounds write. This issue affects HHVM prior to 4.56.2, all versions between 4.57.0 and 4.78.0, 4.79.0, 4.80.0, 4.81.0, 4.82.0, 4.83.0.

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
Hhvm Facebook * 4.56.2 (excluding)
Hhvm Facebook 4.57.0 (including) 4.78.1 (excluding)
Hhvm Facebook 4.79.0 (including) 4.79.0 (including)
Hhvm Facebook 4.80.0 (including) 4.80.0 (including)
Hhvm Facebook 4.81.0 (including) 4.81.0 (including)
Hhvm Facebook 4.82.0 (including) 4.82.0 (including)
Hhvm Facebook 4.83.0 (including) 4.83.0 (including)
Hhvm Ubuntu bionic *
Hhvm Ubuntu trusty *
Hhvm Ubuntu xenial *

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