CyberSecBulletin
CVE-2019-3568Exploited in the wildNVD status: Analyzed

WhatsApp VOIP Stack Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2019-3568 is a critical-severity out-of-bounds write vulnerability in WhatsApp for Android from Facebook, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2.19.134 as the first without the flaw, so updating WhatsApp for Android to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on April 19, 2022, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update WhatsApp for Android to 2.19.134 or a later version.
  2. Update WhatsApp Business for Android to 2.19.134 or a later version.
  3. Update WhatsApp for iOS to 2.19.51 or a later version.
  4. CISA's required action: Apply updates per vendor instructions.
  5. Read the advisory on facebook.com for workarounds and exact fixed builds.
  6. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
FacebookWhatsApp for Android2.19.134; before 2.19.1342.19.134
FacebookWhatsApp Business for Android2.19.44; before 2.19.1342.19.134
FacebookWhatsApp for iOS2.19.51; before 2.19.512.19.51
FacebookWhatsApp Business for iOS2.19.51; before 2.19.512.19.51
FacebookWhatsApp for Windows Phone2.18.348; before 2.18.3482.18.348
FacebookWhatsApp for Tizen2.18.15; before 2.18.152.18.15
WhatsappWhatsappbefore 2.18.15; before 2.18.348; before 2.19.51; before 2.19.1342.18.15, 2.18.348, 2.19.51, 2.19.134
WhatsappWhatsapp Businessbefore 2.19.44; before 2.19.512.19.44, 2.19.51

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)
CVSS 2.07.5HighNVD

Official description

A buffer overflow vulnerability in WhatsApp VOIP stack allowed remote code execution via specially crafted series of RTCP packets sent to a target phone number. The issue affects WhatsApp for Android prior to v2.19.134, WhatsApp Business for Android prior to v2.19.44, WhatsApp for iOS prior to v2.19.51, WhatsApp Business for iOS prior to v2.19.51, WhatsApp for Windows Phone prior to v2.18.348, and WhatsApp for Tizen prior to v2.18.15.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • 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 discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Out-of-bounds Write vulnerabilities

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