Verification code forwarding attack

Hossein Siadati, Toan Nguyen, Nasir Memon

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Major Internet service providers deploy SMS-based verification mechanisms to fortify the security of users’ accounts for critical actions such as password reset and logging in from a new computer. In this paper, we describe a new type of phishing attack where an attacker triggers the delivery of a verification code from a service provider to a user and lures the user to forward the code to him so that he can bypass the SMS verification process. We call this a Verification Code Forwarding Attack (VCFA). The attacker can use VCFA to reset a password of a user’s account or to get access to a 2-factor enabled account which he already knows its password (e.g., through leaked databases). We attribute the success of this attack to the lack of an effective and usable means for users to verify the service provider, the lack of context for the message sent, and an assumption about users’ understanding of the authentication process. To show the susceptibility of the users to such an attack, we conducted an experiment with 20 mobile phone users and found that more than 25% of users were vulnerable against this type of attack. A semi-structured interview with the subjects of the experiment and a survey of 100 subjects on Amazon Mechanical Turk were done to explore possible causes for the success of this type of attack. We also discuss possible remediation.

Original languageEnglish (US)
Title of host publicationTechnology and Practice of Passwords - 9th International Conference, PASSWORDS 2015, Proceedings
EditorsPer Thorsheim, Frank Stajano, Graeme Jenkinson, Stig F. Mjolsnes
PublisherSpringer Verlag
Number of pages7
ISBN (Print)9783319299372
StatePublished - 2016
Event9th International Conference on Technology and Practice of Passwords, PASSWORDS 2015 - Cambridge, United Kingdom
Duration: Dec 7 2015Dec 9 2015

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other9th International Conference on Technology and Practice of Passwords, PASSWORDS 2015
Country/TerritoryUnited Kingdom

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


Dive into the research topics of 'Verification code forwarding attack'. Together they form a unique fingerprint.

Cite this