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PYSEC-2026-1677
No affected components available
Summary
While examining the "App Link assetlinks.json file could not be found" vulnerability detected by MobSF, we, as the Trendyol Application Security team, noticed that a GET request was sent to the "/.well-known/assetlinks.json" endpoint for all hosts written with "android:host". In the AndroidManifest.xml file.
Since MobSF does not perform any input validation when extracting the hostnames in "android:host", requests can also be sent to local hostnames. This may cause SSRF vulnerability.
Details
Example <intent-filter structure in AndroidManifest.xml:
<intent-filter android:autoVerify="true">
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:host="192.168.1.102/user/delete/1#" android:scheme="http" />
</intent-filter>
We defined it as android:host="192.168.1.102/user/delete/1#". Here, the "#" character at the end of the host prevents requests from being sent to the "/.well-known/assetlinks.json" endpoint and ensures that requests are sent to the endpoint before it.
<img width="617" alt="image" src="https://github.com/MobSF/Mobile-Security-Framework-MobSF/assets/150332295/c570cb00-e947-4ad7-af80-26d46c0ad3f7">PoC
https://drive.google.com/file/d/1nbKMd2sKosbJef5Mh4DxjcHcQ8Hw0BNR/view?usp=share_link
Impact
The attacker can cause the server to make a connection to internal-only services within the organization's infrastructure.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data. There is a low impact on the availability of the system.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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