Backdoor found in 2G mobile data encryption standard

Cryptanalysis of GPRS Encryption Algorithms GEA-1 suggest intentional weakness

GPRS is the mobile data standard for GSM mobile phones. It's from the 2G era, and is old and slow. GEA-1 is an encryption algorithm used with GPRS.

Excerpt from the abstract:
"This paper presents the first publicly available cryptanalytic attacks on the GEA-1 and GEA-2 algorithms."

[..]

"This unusual pattern indicates that the weakness is intentionally hidden to limit the security level to 40 bit by design."

So in other words: GPRS was intentionally backdoored.

https://eprint.iacr.org/2021/819

Comments
https://news.ycombinator.com/item?id=27686422

https://apnews.com/article/europe-technology-business-3bddc473856a9af259feb511f58a51d3

https://link.springer.com/chapter/10.1007%2F978-3-030-77886-6_6

https://www.sueddeutsche.de/wirtschaft/handy-gprs-verschluesselung-1.5323228

#backdoor #2g #gprs #encryption

Bombshell Report Finds Phone Network Encryption Was Deliberately Weakened

Comments
https://news.ycombinator.com/item?id=27686422

via www.vice.com

#backdoor #2g #gprs #encryption

Grant H (@Digital_Cold): "Our paper on emulating basebands for security analysis has been accepted at NDSS! We found multiple critical pre-auth vulnerabilities in the 2G and 4G implementations on Samsung and MediaTek basebands. Check out the paper or keep reading to learn more https://hernan.de/research/papers/firmwire-ndss22-hernandez.pdf"

"Baseband processors are where protocols like GSM and LTE live. Unlike the application processors which run apps and OSes like Android, they run complicated real-time operating systems in the background, which are difficult to analyze and understand."

"Basebands today are gigantic, multi-million line software and hardware projects. Besides the complex cellular standards, they add on top ASN.1 decoders, DHCP, DNS, SIP, audio codecs, TLS, HTTP, XML parsers and so much more. Oh and did I mention TCP/IP stacks?"

"Let’s say you wanted to audit all of this. You’d get bogged down reverse engineering binary-only firmware - no small task given the size of modern basebands. How about fuzzing? Fuzzing a real phone over-the-air can be done, but it's slow and root-causing of crashes is not easy."

"That’s why we created FirmWire which let’s us fuzz unmodified baseband firmware images extracted from vendor updates. We do this using full-system emulation to recreate the hardware environment around the firmware image enabling us to actually boot and run the baseband."

Grant H (@Digital_Cold): "Using these capabilities, we implemented several fuzzers for the GSM CC, GSM SM, as well as the LTE RRC protocol. Some of the bugs we found allow remote code execution for literally anyone who can set up a fake base station, and have been assigned a critical severity score." | nitter – https://nitter.net/Digital_Cold/status/1481060540109803523#m

#Cellular #2G #4G

GSM Voice Decryption From Start To Finish (2G Non-Hopping Only)

The GSM data used in the making of this video was recorded and decrypted with unanimous consent from the owner(s) for the purpose of demonstrating the 2G decoding features of gr-gsm and for evaluating cellular network security.

Due to it's complexity and difficulty, decoding 2G phone calls is considered by most to be the hardest task to accomplish in the realm of GSM decoding. Differing voice codecs, varying channel data rates, arbitrary allocation of frequency hopping and carrier-specific network configurations add too many variables into the mix to make it a straight-forward enough goal to achieve.

I showcase the entire 2G voice decryption process from start to finish, excluding the actual recording of the GSM data

This video was made for purposes of education & experimentation only #IMSI-CATCHING, #SMS-SNIFFING and voice call #interceptior on #CELLULAR #NETWORKS is illegal & punishable by hefty fines & imprisonment

#GSM #2G #SDR #GRsdm