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Vulnerability in the WIB SIM-browser allows attackers to take control of millions of mobile phones around the world


Previously, E Hacking News reported on the Simjacker vulnerability, which allows to monitor the owners of the phones.

Simjacker is the first real attack where the malicious instructions are sent directly in the SMS message. Interestingly, messages are not stored in either inbox or outbox, so everything happens completely unnoticed by the victim.

According to the researchers, attackers can exploit the vulnerability regardless of the brand of the user's device. A similar vulnerability was recorded on devices of many manufacturers, including Apple, Samsung, Google, HUAWEI and others.

According to Adaptive Mobile Security experts, the vulnerability has been exploited for at least two years by highly sophisticated cyber criminals (most likely working for the government) to spy on users.

Ginno Security Lab experts claim they identified similar kind of vulnerabilities in 2015 and this is the first time they are publishing the details.

Adaptive Mobile Security said that everything starts with sending a malicious SMS-message. It can be sent from a phone, GSM modem or even a computer. After opening, this malicious message launches the S@T Browser program installed on each SIM card, as mobile operators use it to provide their services. In this way, attackers can gain full control of the victim's phone.

The company Ginno Security Lab claims that they have found vulnerability in both WIB simcard-browser and S@T simcard-browsers.

"The Wireless Internet Browser (WIB) is specified by SmartTrust and is the market leading solution for SIM toolkit based browsing".

By sending a malicious SMS message to the victim's phone number, an attacker can exploit vulnerabilities in the WIB simcard-browser to remotely gain control of the victim's mobile phone to perform malicious actions.  In their demo, they remotely made a call from victim's phone to another phone.

The impact of the vulnerability in WIB is spreading around the world and putting hundreds of millions of telecommunication subscribers worldwide at risk. The security vulnerability comes from the SIM card, does not depend on mobile phones or the mobile phone operating system, so every mobile phone is affected.

According to the researchers, one of the main reasons for the existence of Simjacker vulnerability today is the use of outdated technologies in SIM cards, the specifications of which have not been updated since 2009. Experts have already information their findings to the GSM Association, a trade organisation that represents the interests of mobile operators around the world.

Simjacker Exploits S@T Browser to Affect a Billion Users



Platform agnostic attack, Simjacker allows hackers to remotely exploit the victims' phone by sending a SMS which contains a malicious code; the code gives instructions to the universal integrated circuit card (UICC)/ SIM card placed inside the targeted device to retrieve and carry out sensitive commands.

The attack is set into motion as soon as the 'attack SMS' sent via another remote handset, is received by the targeted device. The process involves a series of SIM Toolkit (STK) directions particularly configured to be sent on to the SIM Card inside the victim's device.

To ensure a proper execution of these instructions, Simjacker exploits the S@T Browser, which is a software found in SIM cards. After receiving the 'attack SMS', SIM card resorts to the S@T Browser library for setting up the execution friendly environment which can trigger logic on the infected device.

S@T Browser, a legacy browser technology placed inside the SIM cards on a number of handsets, was typically used to send promotional messages or spam text messages. However, the attackers went on exploiting it for obtaining device's location and its unique International Mobile Equipment Identity (IMEI).

The attacker sends a SMS to the S@T browser asking it for the aforementioned information which it would obtain and store on to the SIM card. Then, the attacker would send another SMS to acquire the stored information. These messages are send and received in binary codes, unlike regular messages. It doesn't alert the victim in any manner and hence qualifies to be a highly effective tool for attacking mobile phones via messages.

Referencing from the findings of mobile carrier security company AdaptiveMobile Security, 

"The main Simjacker attack involves an SMS containing a specific type of spyware-like code being sent to a mobile phone, which then instructs the SIM Card within the phone to ‘take over’ the mobile phone to retrieve and perform sensitive commands." 

"We believe this vulnerability has been exploited for at least the last two years by a highly sophisticated attacker group." The report reads. 

Notably, the exploit is working as a lot of operators are failing to check the origin of these binary codes (SMS), which can be blocked by configuring the firewall technology in their corresponding networks, advises AdaptiveMobile.