Dendrobatus Azureus<p>This is something you need to read in order to believe</p><p>subject: VoLTE<br>provider O2 UK<br>nightmare: infosec</p><p>Enormous. Outragerous are some of the words I would use. Take you time to read and learn because they are not the only culprits on the planet with such bad data protection practices</p><p>Excerpt</p><p>>></p><p>Quite quickly I realised something was wrong. The responses I got from the network were extremely detailed and long, and were unlike anything I had seen before on other networks. The messages contained information such as the IMS/SIP server used by O2 (Mavenir UAG) along with version numbers, occasional error messages raised by the C++ services processing the call information when something went wrong, and other debugging information. However, most notable were a set of five headers near the bottom of the message:</p><p>SIP Msg<br>...<br> P-Mav-Extension-IMSI: 23410123456789<br> P-Mav-Extension-IMSI: 23410987654321<br> P-Mav-Extension-IMEI: 350266809828927<br> P-Mav-Extension-IMEI: 350266806365261<br> ...<br> Cellular-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=2341010037A60773;cell-info-age=26371</p><p>Synthesised excerpt of IMS signalling message for demonstration; not a genuine IMEI/IMSI/cell ID.</p><p>Two sets of IMSIs, two sets of IMEIs, and a Cell ID header. How curious…</p><p>Sure enough, when comparing both the IMSIs and IMEIs in the message to those of my own devices, I had been given both the IMSI and IMEI of my phone which initiated the call, but also the call recipient's.</p><p><<<br>^Z</p><p><a href="https://mastodon.bsd.cafe/tags/O2" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>O2</span></a> <a href="https://mastodon.bsd.cafe/tags/UK" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>UK</span></a> <a href="https://mastodon.bsd.cafe/tags/TeleCom" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>TeleCom</span></a> <a href="https://mastodon.bsd.cafe/tags/InfoSec" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>InfoSec</span></a> <a href="https://mastodon.bsd.cafe/tags/DataLeak" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>DataLeak</span></a> <a href="https://mastodon.bsd.cafe/tags/WTF" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>WTF</span></a> </p><p><a href="https://mastdatabase.co.uk/blog/2025/05/o2-expose-customer-location-call-4g/" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://</span><span class="ellipsis">mastdatabase.co.uk/blog/2025/0</span><span class="invisible">5/o2-expose-customer-location-call-4g/</span></a></p>