CVE-2019-3954

published 2019-06-19

CVE-2019-3954: Stack-based buffer overflow in Advantech WebAccess/SCADA 8.4.0 allows a remote, unauthenticated attacker to execute arbitrary code by sending a crafted IOCTL…

Priority P2 67 critical 9.8 CVSS 3.0

AV N AC L PR N UI N S U C H I H A H

Stack-based buffer overflow in Advantech WebAccess/SCADA 8.4.0 allows a remote, unauthenticated attacker to execute arbitrary code by sending a crafted IOCTL 81024 RPC call.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
advantech	webaccess	—	—
advantech_webaccess	scada	—	—

Detection & IOCs extracted from sources · hover to see the quote

other IOCTL 81024 RPC call↗

path C:\WebAccess\Node\viewdll1.dll↗

filename viewdll1.dll↗

• → Detect exploitation of CVE-2019-3954 by monitoring for IOCTL 81024 RPC calls to Advantech WebAccess/SCADA nodes, particularly those with oversized attacker-controlled data in the pNode and pProject fields that trigger a stack overflow in VdBroadWinGetLocalDataLogEx(). ↗
• → Look for crash signatures or access violations in viewdll1.dll at VdBroadWinGetLocalDataLogEx+0x15a with EIP/stack overwritten with repeated 0x41 bytes (classic buffer overflow pattern), indicating active exploitation attempts. ↗
• → Monitor for exception handler chain corruption in msvcrt!_output_l triggered from viewdll1.dll sprintf calls, which is the exploitable condition identified for CVE-2019-3954. ↗
• → The format string '%s%s_%s\sysinfo.ini' in viewdll1.dll is the target of the overflow; monitor for abnormally large RPC input buffers destined for WebAccess Node processes that would overflow the fixed-size stack buffer at var_634. ↗

• · The vulnerability is unauthenticated and remotely exploitable — no credentials are required to trigger the IOCTL 81024 RPC stack overflow, meaning network-level access to the WebAccess Node RPC service is sufficient for exploitation. ↗
• · The vulnerable code path is specifically within the VdBroadWinGetLocalDataLogEx() function in viewdll1.dll; patching or replacing this DLL is required to remediate the vulnerability in Advantech WebAccess/SCADA 8.4.0. ↗

CVSS provenance

nvd v3.0 9.8 CRITICAL CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd v2.0 7.5 HIGH AV:N/AC:L/Au:N/C:P/I:P/A:P

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