ZDI-07-044: BakBone NetVault Reporter Scheduler Heap Overflow Vulnerability

[zdi-disclosures@xxxxxxxx]

ZDI-07-044: BakBone NetVault Reporter Scheduler Heap Overflow
            Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-07-044.html
July 25, 2007

-- CVE ID:
CVE-2007-3911

-- Affected Vendor:
BakBone

-- Affected Products:
BakBone NetVault Reporter 3.5 < Update4

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since July 24, 2007 by Digital Vaccine protection
filter ID 5215. For further product information on the TippingPoint IPS:

    http://www.tippingpoint.com 

-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
systems with affected installations of BakBone NetVault Reporter. User
interaction is not required to exploit this vulnerability.

The specific flaw exists both within the scheduler client
(clsscheduler.exe) listening on TCP port 7978 and the scheduler server
(srvscheduler.exe) listening on TCP port 7977. In both cases an
exploitable heap corruption can occur during the processing of overly
long filename arguments to the "GET" and "POST" requests. Code
execution is possible under the context of the SYSTEM user.

When searching for a termination/whitespace character ("\r\t\n") a heap
chunk is being used to hold the data. Due to the lack of bounds checking
on this heap chunk an overflow occurs when a long string without any of
the above special characters are encountered. The vulnerable code
appears below.

    0x00466C07 mov     al, [esi+ebp]
    0x00466C0A cmp     al, 20h
    0x00466C0C jz      short loc_466C84
    0x00466C0E cmp     al, 9
    0x00466C10 jz      short loc_466C84
    0x00466C12 cmp     al, 0Ah
    0x00466C14 jz      short loc_466C84
    0x00466C16 cmp     al, 0Dh
    0x00466C18 jz      short loc_466C84
    0x00466C1A push    1
    0x00466C1C inc     esi
    0x00466C1D push    1
    0x00466C1F lea     edx, [esi+ebp]   ; heap chunk
    0x00466C22 push    edx              ; readfds
    0x00466C23 mov     ecx, edi
    0x00466C25 call    sub_4645C0       ; recv 1 byte
    0x00466C2A cmp     eax, 0FFFFFFFFh
    0x00466C2D mov     [ebx+272Ch], eax
    0x00466C33 jnz     short loc_466C07 ;loop


-- Vendor Response:
BakBone has addressed this issue in NetVault Report Manager v3.5 Update4
available for download from:

    http://www.bakbone.com/products/downloads/default.asp

-- Disclosure Timeline:
2007.02.23 - Vulnerability reported to vendor
2007.07.24 - Digital Vaccine released to TippingPoint customers
2007.07.25 - Public release of advisory

-- Credit:
This vulnerability was discovered by Tenable Network Security.

-- About the Zero Day Initiative (ZDI):
Established by TippingPoint, a division of 3Com, The Zero Day Initiative
(ZDI) represents a best-of-breed model for rewarding security
researchers for responsibly disclosing discovered vulnerabilities.

Researchers interested in getting paid for their security research
through the ZDI can find more information and sign-up at:

    http://www.zerodayinitiative.com

The ZDI is unique in how the acquired vulnerability information is used.
3Com does not re-sell the vulnerability details or any exploit code.
Instead, upon notifying the affected product vendor, 3Com provides its
customers with zero day protection through its intrusion prevention
technology. Explicit details regarding the specifics of the
vulnerability are not exposed to any parties until an official vendor
patch is publicly available. Furthermore, with the altruistic aim of
helping to secure a broader user base, 3Com provides this vulnerability
information confidentially to security vendors (including competitors)
who have a vulnerability protection or mitigation product.

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