CVE-2018-1000654

What it actually does

Denial-of-service via unbounded CPU consumption (reaching 100%) during ASN.1 object identifier expansion in _asn1_expand_object_id when a crafted file is parsed with asn1Parser, eventually causing the process to be killed.

Why it matters to the business

Services that parse untrusted ASN.1 data can become unresponsive or crash, interrupting operations; the issue has been public for years with available exploits but low and stable exploitation probability, reducing immediate urgency while still requiring remediation on affected deployments.

How an attack unfolds

An attacker prepares a malicious ASN.1 file that triggers the parsing flaw, then supplies it to any application (such as Apache via Bitnami) that invokes libtasn1 parsing routines; the target process enters a tight loop consuming full CPU until it is terminated or the system becomes unavailable.

How to fix it

Upgrade affected packages to fixed versions; for apache (Bitnami) deploy version 2.4.48 or later that incorporates the corrected libtasn1.

How to confirm the fix worked

Verify installed libtasn1 or dependent package versions against the fixed release; in a test environment replay the public proof-of-concept file and confirm absence of sustained 100% CPU usage.

Typical attack path

1. Generate a crafted ASN.1 file containing a malicious object identifier
2. Deliver the file to the target application through any parsing entry point
3. Trigger asn1Parser or equivalent libtasn1 call on the file
4. Sustain high CPU consumption leading to denial of service

How to detect it

Monitor process CPU utilization spikes correlated with ASN.1 parsing activity; review application logs for repeated or failed parsing of ASN.1 content and inspect any retained malicious test files.

What your security team should do

• Prioritize upgrade of apache (Bitnami) to 2.4.48+ on all instances
• Inventory other products that embed libtasn1 and schedule updates
• Add file-type and size checks before ASN.1 parsing where feasible