OpenSSL 1.0.2a fix several security issues, one of them let crash TLSv1.2 based services remotelly from internet.
Regarding to the TLSv1.2 RFC, this version of TLS provides a "signature_algorithms" extension for the client_hello.
Regarding to the TLSv1.2 RFC, this version of TLS provides a "signature_algorithms" extension for the client_hello.
 |
| Data Structures |
If a bad signature is sent after the renegotiation, the structure will be corrupted, becouse structure pointer:
s->c->shared_sigalgs will be NULL, and the number of algorithms:
s->c->shared_sigalgslen will not be zeroed.
Which will be interpreted as one algorithm to process, but the pointer points to 0x00 address.
s->c->shared_sigalgs will be NULL, and the number of algorithms:
s->c->shared_sigalgslen will not be zeroed.
Which will be interpreted as one algorithm to process, but the pointer points to 0x00 address.
Then tls1_process_sigalgs() will try to process one signature algorithm (becouse of shared_sigalgslen=1) then sigptr will be pointer to c->shared_sigalgs (NULL) and then will try to derreference sigptr->rhash.
This mean a Segmentation Fault in tls1_process_sigalgs() function, and called by tls1_set_server_sigalgs() with is called from ssl3_client_hello() as the stack trace shows.
 |
| StackTrace |
The following code, points sigptr to null and try to read sigptr->rsign, which is assembled as movzbl eax, byte ptr [0x0+R12] note in register window that R12 is 0x00
 |
| Debugger in the crash point. |
 |
| radare2 static decompiled |
Get David A. Ramos' proof of concept exploit here
More articles
- Hack Tool Apk No Root
- Hacking Tools And Software
- Pentest Tools Open Source
- Pentest Tools Linux
- Pentest Tools Android
- Pentest Tools Tcp Port Scanner
- Hack Apps
- Hack Tools Online
- Hacking Tools 2019
- What Is Hacking Tools
- Hack Tools Online
- Hack App
- What Is Hacking Tools
- Hacker Tools Free
- Nsa Hack Tools Download
- Hacking Tools Github
- New Hacker Tools
- Hacker Tools For Ios
- What Are Hacking Tools
- Growth Hacker Tools
- Hack Tool Apk No Root
- Hack Apps
- Best Pentesting Tools 2018
- Hack And Tools
- Nsa Hacker Tools
- Pentest Tools For Ubuntu
- Pentest Tools For Ubuntu
- Pentest Tools Android
- Nsa Hack Tools
- Pentest Reporting Tools
- How To Hack
- Hack Tools For Pc
- Hacker Tools 2020
- Pentest Tools Open Source
- Pentest Tools Alternative
- Hacking Tools For Kali Linux
- Blackhat Hacker Tools
- Pentest Tools Bluekeep
- Hacking Tools Free Download
- Hacker Tools Hardware
- Pentest Tools Review
- Blackhat Hacker Tools
- New Hacker Tools
- Free Pentest Tools For Windows
- Hacking Tools Pc
- Nsa Hacker Tools
- Hacker Tool Kit
- Usb Pentest Tools
- Hacking Tools
- Pentest Tools For Mac
- Hacking Tools Windows 10
- Hacker Tools Hardware
- Hacker Tools 2020
- Hacker Tools For Pc
- Hack Tools For Mac
- New Hacker Tools
- Pentest Tools Url Fuzzer
- Hacks And Tools
- Hacker Tools Windows
- Hackers Toolbox
- Nsa Hacker Tools
- Hacker Tools For Pc
- Hacking Tools For Windows 7
- Hacking Tools 2020
- Hacker Tools Mac
- Easy Hack Tools
- Pentest Tools Online
- Hack Tool Apk
- Pentest Tools For Android
- Hacker Tools Software
- Hack Tools
