GridinSoft Threat Intelligence
zlib1.dll threat report
GridinSoft Anti-Malware detection
Detected by GridinSoft before you download
The current ThreatInfo record shows this exact file hash detected as PUP.SystemOptimizer. Download GridinSoft Anti-Malware to scan the device, confirm whether this file is present, and remove the detected object if it is found.
- Detection name
- PUP.SystemOptimizer
- Recommended action
- Scan and remove
- Last analysis
- 2025-03-16 23:01:38 (a year ago)
- File hash
- c126d5728f3e6de03fc83c82f0cfb5bf
Why it matters
Why GridinSoft flags this file
GridinSoft identifies the sample as PUP.SystemOptimizer, part of the PUP threat category.
Potentially unwanted programs, bundlers, installers, and utilities with intrusive behavior. Related PUP reports help compare this file with nearby detections, publishers, and hashes.
First seen 2025-03-16 23:01:38 (a year ago); latest analysis 2025-03-16 23:01:38 (a year ago).
Product metadata: zlib.
Signed by Qiwang Computer. The signature is reported as valid, but signed files can still be bundled or abused.
ThreatInfo has seen this file in user or system paths listed below. Unexpected locations increase the need for local verification.
Recommended action
What to do next
- Compare the MD5 above with the file found on the device.
- Check whether the file appears in the observed locations or under one of the alternate names.
- Run GridinSoft Anti-Malware to confirm the detection and remove the file if it is present. Review the PUP category for related samples and common context.
File context
zlib1.dll is a Windows file recorded in the ThreatInfo database. It is associated with zlib. The current detection status is PUP.SystemOptimizer, based on the latest analysis from 2025-03-16 23:01:38 (a year ago). ThreatInfo groups this verdict with PUP reports for broader family-level investigation.
If zlib1.dll appears on your computer unexpectedly, treat it as suspicious. Check its location, digital signature, and recent system changes before allowing it to run. A full anti-malware scan is recommended when this file is detected as PUP.SystemOptimizer.
File Details
| Product Name: | zlib |
| MD5: | c126d5728f3e6de03fc83c82f0cfb5bf |
| Size: | 63 KB |
| First Published: | 2025-03-16 23:01:38 (a year ago) |
| Latest Published: | 2025-03-16 23:01:38 (a year ago) |
| Status: | PUP.SystemOptimizer (on last analysis) | |
| Analysis Date: | 2025-03-16 23:01:38 (a year ago) |
Detection screenshot
The screenshot is a visual record of a GridinSoft Anti-Malware detection for this sample. Use the hash and metadata above as the primary identifiers when comparing the file on your system.
Overview
| Signed By: | Qiwang Computer |
| Status: | Valid |
The signature on zlib1.dll is reported as valid. A valid signature helps confirm publisher identity, but it does not automatically make the file safe if the installer was bundled, abused, or downloaded from an untrusted source.
Common Places:
| %programfiles% |
ThreatInfo has observed zlib1.dll in the locations listed above. Files found in temporary folders, user profile folders, startup locations, or unusual application directories should be reviewed more carefully than files installed under a known program directory.
Geographic signal
Observed country distribution
ThreatInfo has seen zlib1.dll across 1 countries. Use this signal to compare local evidence with where the sample is most often reported.
The strongest geographic signal for this file is Greece with 100.0% of observed hits. Geographic distribution can help identify targeted campaigns, regional software bundles, or where a file is most commonly reported.
OS Version:
The most common operating system signal for zlib1.dll is Windows 10 with 100.0% of observed hits. If your system differs from the common profile, check whether the file was introduced by a specific installer, archive, or removable device.
Analysis
zlib1.dll is identified as pe for 32-bit systems. The subsystem is Windows GUI. PE header values are useful for triage, especially when they do not match the expected publisher, product, or release timeline.
PE Sections:
Section layout highlights raw-size concentration, repeated names, packer markers, and hashes that can be compared across related samples.
c758d703412b079681936e5c60c5080b
3152b1002f44bfacb6198a3316775909
de7a3eab5a56e099b2791c1ecfb9c39b
b932cf50c0e8cbb81b132fbe559b343d
f7c1ccbc1b3eeb94d081424363cc02f4
PE section names and hashes can reveal packing, injected resources, or unusual build artifacts. Sections with uncommon names, very large raw data, or hashes that differ from a trusted copy deserve additional review.
Report conclusion
GridinSoft detects this file as PUP.SystemOptimizer
This report identifies zlib1.dll by MD5 c126d5728f3e6de03fc83c82f0cfb5bf. It is part of the PUP report group. If the same file is present on your device, scan the system and remove the detected object after confirming the hash and location.