How I Tracked My Girlfriend’s Location and Contacts Using IP Lookup and a Custom APK

0x0 Origin

The author notices his girlfriend, who used to come home early, staying out late and becoming distant, prompting him to investigate.

0x1 Getting Her IP Address

He first tries to obtain GPS data from photos, but none contain location info. He then discovers Sohu’s public API http://pv.sohu.com/cityjson?ie=utf-8 which returns IP, ID, and city name. Testing shows the IP returned in WeChat’s built‑in browser differs from a normal browser because WeChat uses a proxy.

To bypass this, he uses a short‑link service that redirects the URL to the device’s native browser, allowing the script to capture the real IP.

<script src="http://pv.sohu.com/cityjson?ie=utf-8"></script>
<script type="text/javascript">document.write(returnCitySN["cip"]+","+returnCitySN["cname"]);</script>

He then queries an IP‑lookup site to approximate her location, noting a discrepancy of about 16 km between the IP‑based location and her claimed workplace.

0x2 Extracting Call Records and Contacts

Using the E4A tool (a Chinese visual Android development environment), he builds an APK that embeds components for the phonebook, SMS, and call log. He writes code that, when the app runs, sends the victim’s contacts and call history to a server.

After compiling the APK and distributing it via a short link, he convinces his girlfriend to install it by sending a “520” (I love you) message with the download URL.

0x3 Social Engineering the Third Party

He imports the unknown male’s phone number (found in the contacts) into his phone, adds him on QQ, and pretends to be an old classmate organizing a reunion. The male accepts the request, and the author discovers a photo of his girlfriend’s leg, confirming the affair.

0x4 Conclusion

Realizing the betrayal, the author confronts his girlfriend and ends the relationship.