iPhone Security Issue Opens Door to SMS Spoofing

ios messages iconJailbreak hacker and security researcher pod2g today revealed a newly-discovered security issue in all versions of iOS that could allow malicious parties to spoof SMS messages, making a recipient think that a message came from a trusted sender when it in fact came from the malicious party.

The issue is related to iOS's handling of User Data Header (UDH) information, an optional section of a text payload that allows users to specify certain information such as changing the reply-to number on a message to something other than the sending number. The iPhone's handling of this optional information could leave recipients open to targeted SMS spoofing attacks.

In the text payload, a section called UDH (User Data Header) is optional but defines lot of advanced features not all mobiles are compatible with. One of these options enables the user to change the reply address of the text. If the destination mobile is compatible with it, and if the receiver tries to answer to the text, he will not respond to the original number, but to the specified one.

Most carriers don't check this part of the message, which means one can write whatever he wants in this section : a special number like 911, or the number of somebody else.

In a good implementation of this feature, the receiver would see the original phone number and the reply-to one. On iPhone, when you see the message, it seems to come from the reply-to number, and you [lose] track of the origin.

pod2g highlights several ways in which malicious parties could take advantage of this flaw, including phishing attempts linking users to sites collecting personal information or spoofing messages for the purposes of creating false evidence or gaining a recipient's trust to enable further nefarious action.

In many cases the malicious party would need to know the name and number of a trusted contact of the recipient in order for their efforts to be effective, but the phishing example shows how malicious parties could cast broad nets hoping to snare users by pretending to be a common bank or other institution. But with the issue resulting in recipients being shown the reply-to address, an attack could be discovered or thwarted simply by replying to the message, as the return message would go to the familiar contact rather than the malicious one.

Top Rated Comments

JAT Avatar
120 months ago
I think we could use a slight rewrite of the article. It didn't say "malicious party" nearly often enough for me.
Score: 9 Votes (Like | Disagree)
gotluck Avatar
120 months ago


Nope. :apple:

But i'm not surprised it didn't come from someone legit.

Pod2g is quite legit in my book.
Score: 6 Votes (Like | Disagree)
miniConvert Avatar
120 months ago
This makes no sense. You don't need to use UDH tricks to 'spoof' the sender ID on a text message, you just set whatever sender ID you want to use. Any text message can contain up to 16 digits or 11 alphanumeric characters of sender ID, and there's absolutely nothing that ensures this data is somehow verified or official.

Just as with an email you can, technically, originate it from wherever the hell you like, so can you with a text message.

This 'discovery' is not a discovery at all. In fact, it doesn't seem to be a problem at all. It would only be a problem if the sender ID displayed on the iPhone could be one thing, but the destination of the reply text messages could actually be something else that the user had no knowledge of. Correct me if I'm wrong, but in this instance the user is fully aware of the number they're texting. So no problem.

And yes, I know SMS.
Score: 6 Votes (Like | Disagree)
Uncle Ruckus Avatar
120 months ago
Apple get you act together.

Uncle Ruckus no relations.
Score: 6 Votes (Like | Disagree)
miniConvert Avatar
120 months ago
Agree with this. You are correct, this is not possible. When a reply-to address is specified iOS displays that and ignores the sender.
Yeah, I'm pretty sure this story is without merit and should be taken down. Simply a misunderstanding/lack of understanding about how SMS works.
Score: 5 Votes (Like | Disagree)
theBB Avatar
120 months ago
It is easy to spoof caller ID and fool every phone on earth. How is this any more dangerous?
Score: 5 Votes (Like | Disagree)

Related Stories

General Apps Messages

Android iMessage Competitor Puts Pressure on Apple

Friday July 30, 2021 3:15 am PDT by
Google and the three major U.S. carriers, including Verizon, AT&T, and T-Mobile, will all support a new communications protocol on Android smartphones starting in 2022, a move that puts pressure on Apple to adopt a new cross-platform messaging standard and may present a challenge to iMessage. Verizon recently announced that it is planning to adopt Messages by Google as its default messaging...
iphone 13 teal with text

Apple Begins Preparation for iPhone 13 Production Ahead of Fall Launch

Monday June 28, 2021 3:29 am PDT by
We're just a few months away from when Apple is expected to reveal the 2021 iPhone, dubbed the "iPhone 13." In preparation for its launch, it has been pulling in shipments of different components needed to produce the new iPhones, according to a report from DigiTimes. In years past, Apple released its latest iPhone lineup, alongside a new Apple Watch, during a September event at Apple Park....
studio buds family

Beats Studio Buds Debuting Today With Active Noise Cancellation, Stemless Design, and More for $150

Monday June 14, 2021 8:00 am PDT by
We've seen a lot of teasers about the Beats Studio Buds over the past month since they first showed up in Apple's beta software updates, and today they're finally official. The Beats Studio Buds are available to order today in red, white, and black ahead of a June 24 ship date, and they're priced at $149.99. The Studio Buds are the first Beats-branded earbuds to truly compete with AirPods...
bluetti eb70 main

MacRumors Giveaway: Win a Bluetti EB70 Portable Power Station and 200W Solar Panel

Friday September 3, 2021 11:13 am PDT by
For this week's giveaway, we've teamed up with MAXOAK to offer MacRumors readers a chance to win a Bluetti portable power station and an accompanying solar panel. Bluetti makes a range of portable power station options that are useful for camping, emergencies, power outages, off-grid living, and similar situations. The Bluetti EB70 is a solid middle of the road option that offers 716Wh and...
apple privacy

Apple Publishes FAQ to Address Concerns About CSAM Detection and Messages Scanning

Monday August 9, 2021 1:50 am PDT by
Apple has published a FAQ titled "Expanded Protections for Children" which aims to allay users' privacy concerns about the new CSAM detection in iCloud Photos and communication safety for Messages features that the company announced last week. "Since we announced these features, many stakeholders including privacy organizations and child safety organizations have expressed their support of...
macos catalina legacy system extension alert

Apple Begins Warning Users That 'Legacy System Extensions' Won't Work With a Future Version of macOS

Wednesday March 25, 2020 9:53 am PDT by
Apple has shared a new support document that indicates kernel extensions — which it calls "legacy system extensions" — will not be compatible with a future version of macOS because they "aren't as secure or reliable as modern alternatives."System extensions are a category of software that works in the background to extend the functionality of your Mac. Some apps install kernel extensions, which...
General Spotify Feature

Spotify Pauses Plans to Add AirPlay 2 Support to iOS App [Update: Spotify Clarifies]

Friday August 6, 2021 9:07 am PDT by
See update at bottom of article Spotify this week confirmed that its plans to add AirPlay 2 support to its iOS app have been placed on indefinite hiatus. In an online discussion forum post, a Spotify representative said the streaming music service had been working on supporting AirPlay 2, but the company has paused the efforts "for now" due to "audio driver compatibility issues." The...
youtube apple tv

YouTube Discontinuing 3rd-Generation Apple TV App, AirPlay Still Available

Wednesday February 3, 2021 3:09 pm PST by
YouTube is planning to stop supporting its YouTube app on the third-generation Apple TV models, where YouTube has long been available as a channel option. A 9to5Mac reader received a message about the upcoming app discontinuation, which is set to take place in March.Starting early March, the YouTube app will no longer be available on Apple TV (3rd generation). You can still watch YouTube on...
os x mountain lion macs 16x9 2

Apple Makes OS X Lion and Mountain Lion Free to Download

Wednesday June 30, 2021 12:19 pm PDT by
Apple recently dropped the $19.99 fee for OS X Lion and Mountain Lion, making the older Mac updates free to download, reports Macworld. Apple has kept OS X 10.7 Lion and OS X 10.8 Mountain Lion available for customers who have machines limited to the older software, but until recently, Apple was charging $19.99 to get download codes for the updates. As of last week, these updates no...
Pixel Stand 23W 668x445

Google Pixel 6 Rumored to Support 23W Wireless Charging, Beating iPhone 12's MagSafe

Wednesday September 1, 2021 1:54 am PDT by
Google is rumored to be working on a new wireless charging stand that could deliver 23W of charging power to its upcoming Pixel 6 and Pixel 6 Pro phones, according to a leaked inventory image published by Android Police. Image via Android Police. If true, that would beat the iPhone 12's maximum 15W wireless charging speed (or 12W on ‌iPhone 12 mini‌) using Apple's MagSafe charger, and...