Elaborating on the attack, the researchers stated that the attack involves the exploitation of the SIM Card (UICC) component ‘S@T Browser’. By sending a maliciously crafted SMS, an attacker can trigger this component to let the SIM takeover the target device. As stated by the researchers,
The attack exploits the presence of a particular piece of software, called the S@T Browser - that is on the UICC. Once the Simjacker Attack Message is received by the UICC, it uses the S@T Browser library as an execution environment on the UICC, where it can trigger logic on the handset.The attacker can then retrieve sensitive details from the device, such as IMEI and location, via another SMS by triggering the same logic. Whereas, the victim remains unaware of all this process during the attack.
Following the initial steps, the attackers can further expand the scope of the attack to retrieve other data and perform further commands. The researchers are going to present more details about Simjacker at the upcoming Virus Bulletin Conference (VB2019) scheduled for October 2 to 4, 2019, in London.
The probability of further exploitation never diminishes. The researchers believe that the attack threatens over 1 billion users. Essentially, all mobile phones with SIM cards are vulnerable to Simjacker.
Nonetheless, the researchers confirm that they have communicated the vulnerability to the GSM Association, and the SIM alliance. These entities have taken a number of steps to address the problem.
The researchers also urge the mobile operators to block any suspicious messages potentially triggering S@T Browser.
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