CVE-2023-39317

What it actually does

Integer overflow during allocation of the string_lens array in the LXT2 num_dict_entries parser allows out-of-bounds memory access and subsequent arbitrary code execution when a crafted waveform file is opened.

Why it matters to the business

Opening a malicious waveform file can allow an attacker to run arbitrary code on the analyst's workstation, potentially leading to data theft, lateral movement, or ransomware deployment in engineering environments that rely on legacy waveform viewers.

How an attack unfolds

An attacker creates a specially crafted LXT2 file that triggers an integer overflow in the string_lens allocation path. The victim opens the file with the vulnerable application, causing memory corruption that the attacker has arranged to redirect execution to attacker-controlled code.

How to fix it

Upgrade GTKWave to the latest available release that corrects the integer overflow in LXT2 dictionary handling. Until a fixed build is obtained, avoid opening untrusted .lxt2 files and consider sandboxing or disabling the application in high-risk environments.

How to confirm the fix worked

Confirm the installed version is newer than 3.3.115 and test that the application no longer crashes or exhibits memory corruption when processing known-malicious LXT2 test cases. Monitor vendor release notes for explicit mention of the num_dict_entries fix.

Typical attack path

1. Craft malicious LXT2 file exploiting the string_lens integer overflow
2. Deliver the file via email, download link, or shared storage
3. Victim opens the file in the affected waveform viewer
4. Overflow occurs during dictionary entry processing
5. Memory corruption leads to arbitrary code execution

How to detect it

Review system logs and process execution records for GTKWave crashes or unexpected terminations immediately after LXT2 file access. Correlate file-open events with subsequent suspicious child processes or network activity.

• gtkwave
• .lxt2

What your security team should do

• Immediately restrict opening of .lxt2 files from untrusted sources
• Inventory all installations of the affected waveform viewer and prioritize patching
• Add application sandboxing or execution restrictions where feasible
• Watch for vendor updates addressing LXT2 parsing issues