Is The C Programming Language, 2nd Edition_2#.pdf safe?
No antivirus engine detected the PDF, but one sandbox produced uncorroborated credential-access and process-injection indicators that warrant cautious handling.
All 75 antivirus engines returned no detection, including 17 tier-1 engines. However, one sandbox mapped activity to credential access, process injection, and data destruction, while host reputation and all ten child verdicts remain unresolved; avoid opening the PDF outside an updated, isolated reader until those runtime alerts are independently checked.
adff5d5cba6e961898…2ceaa4d1b11623Recommended next actions
Before opening
Do not open it until the source can be verified independently.
If you already opened it
Stop using it, scan the device, and watch for unexpected behavior or security alerts. Get a fresh copy from the original trusted source and verify its exact hash when possible.
Intelligence
The saved assessment, checked against the scan evidence and recorded coverage.
The reasoning behind this verdict
This section explains the evidence supporting the verdict and keeps conflicting or missing signals visible.
All 75 antivirus engines returned no detection, including 17 tier-1 engines. However, one sandbox mapped activity to credential access, process injection, and data destruction, while host reputation and all ten child verdicts remain unresolved; avoid opening the PDF outside an updated, isolated reader until those runtime alerts are independently checked.
The strongest reassuring evidence is that 0 of 75 engines detected the PDF, including all 17 tier-1 engines. One completed sandbox nevertheless mapped activity to T1003, T1055, and T1485 and reported apparent LSASS targeting. These behavioral mappings are concerning, but no malicious sandbox verdict, named family, malicious child, or external-intelligence hit corroborates them. The observed processes and temporary files include Adobe Acrobat components, making environmental attribution or behavioral misclassification plausible. Host reputation was not checked or saved, and all ten inspected child hashes lack determinate verdicts, so those areas cannot be treated as clean. The mixed evidence supports caution rather than a definitive malware-family conclusion.
What We Detected
The PDF received 0 detections from 75 antivirus engines, including no detections from 17 tier-1 engines. It is an established sample first observed 1,009 days ago and carries an embedded-JavaScript tag, but no engine supplied a malware family.
Threat Behavior
One sandbox run mapped activity to T1003, T1055, and T1485, with synthetic alerts for apparent LSASS access and possible process injection. The same run did not produce a malicious sandbox verdict, and the recorded process list prominently contains Adobe Acrobat and Windows components, so attribution to the PDF is not conclusive. Ten written child files were inspected without a known malicious result, although every child verdict remains unresolved. Five IP contacts were recorded, but no complete host-reputation cross-check is available.
What To Do Now
Do not enable embedded content or JavaScript prompts. If the document is needed, obtain it from a trusted source, verify its hash or provenance, and open it only with a fully updated PDF reader in an isolated environment while keeping endpoint protection enabled.
Where this verdict could be wrong4 caveats
- The complete 0/75 detection result, including 17 tier-1 engines without detections, strongly counters the behavioral alerts.
- behaviour.hasMaliciousSandboxVerdict=false, so the completed sandbox did not itself conclude that the run was malware.
- The PDF contains embedded JavaScript according to file.tags, increasing attack surface even though no antivirus engine detected a payload.
- External-intelligence availability is unknown for CIRCL, MalwareBazaar, and YARAify, so those sources neither corroborate nor clear the file.
These are the assessment's weak points. If you believe one applies to your file, report the verdict and we'll re-review it.
- 0/75 antivirus engines reported a detection.
- All 17 tier-1 engines reported no detection.
- behaviour.hasMaliciousSandboxVerdict=false.
- droppedChildren.hasMaliciousChild=false.
- No tier-1 family consensus or named threat family exists.
- Embedded JavaScript is indicated by file.tags.
- One sandbox mapped apparent credential access to T1003.
- One sandbox mapped possible process injection to T1055.
- The runtime record also includes T1485.
- Reputation was not checked for the five contacted IP addresses.
- All 10 dropped-child verdicts are unresolved.
Prefer a trusted publisher or library copy and compare its SHA-256 before use. Keep endpoint protection enabled and open the document only in an updated, isolated PDF reader without permitting embedded scripts.
Coverage & freshness
Complete means the check returned a usable result. It does not mean the file is safe.
Antivirus
Complete0 of 75 engines flagged the file.
Sandbox
Complete1 isolated runtime environment contributed observations.
Network
Partial5 runtime contacts were observed without a completed reputation cross-check.
YARA
Complete3 signature or behavior rules matched.
External intel
Complete3 of 3 independent reference sources completed.
Behavior
Plain-English impact first, then the observed runtime evidence.
Runtime flight recorder
Capture complete- 1isolated sandbox run
- 16MITRE ATT&CK techniques
- 15spawned processes
- 5network contacts
- 40filesystem & mutex artifacts
What this file does
Observed actions and their security significance
High concern: Accessed operating-system credential data, which can expose saved passwords.
High concern: Injected code into another process, a technique that can conceal execution.
Moderate concern: Communicated over a common application protocol; malware can use this for command-and-control.
Note: Collects details about your system.
These are observed capabilities from an isolated analysis. A technique does not prove malicious intent on its own, and the file never ran on your device.
Attack story
Runtime observations grouped by analysis stage. Arrows organize the stages; they do not claim chronology or causality.
Input file
The submitted object
- FileObserved
The C Programming Language, 2nd Edition_2#.pdf
adff5d5cba6e961898aaa35727c9f27e1f77df7b127b974cc62ceaa4d1b11623
01Uploaded file
Processes
Runtime execution
- ProcessObserved
Observed process
C:\Windows\System32\mobsync.exe -Embedding
02Isolated runtime analysis - ProcessObserved
Observed process
"C:\Program Files\Adobe\Acrobat DC\Acrobat\Acrobat.exe" "C:\Users\<USER>\Desktop\document.pdf"
03Isolated runtime analysis - +1 more recorded observation in Analyst mode
Files
Created or changed
- Written fileObserved
acroNGLLog.txt
C:\Users\<USER>\AppData\Local\Temp\acroNGLLog.txt
04Isolated runtime analysis - Written fileObserved
NGL
C:\Users\<USER>\AppData\Local\Temp\NGL\
05Isolated runtime analysis - +1 more recorded observation in Analyst mode
Network
Hosts contacted
- Contacted hostObserved
23.220.188.152
Contact observed during runtime.
06Isolated runtime analysis - Contacted hostObserved
23.208.129.2
Contact observed during runtime.
07Isolated runtime analysis - +1 more recorded observation in Analyst mode
7 recorded facts from one runtime window. Every fact remains independently traceable in Analyst mode.
What this file did when executed
This file was detonated in 1 sandbox and its runtime behaviour was observed.
Adversary techniques mapped to the MITRE ATT&CK framework.
- 23.220.188.152
- 23.208.129.2
- 8.8.8.8
- 104.126.120.135
- 50.16.47.176
- C:\Users\<USER>\AppData\Local\Temp\acroNGLLog.txt
- C:\Users\<USER>\AppData\Local\Temp\NGL\
- C:\Users\<USER>\AppData\Local\Temp\Tmp18C3.tmp
- C:\Users\<USER>\AppData\Local\Temp\Tmp1C2F.tmp
- C:\Users\<USER>\AppData\Local\Temp\A9bw1wmk_1cyu0k4_2ww.tmp
- C:\Users\<USER>\AppData\Roaming\Adobe\Acrobat\DC\JSCache\GlobSettings
- C:\Users\<USER>\AppData\Local\Adobe\Acrobat\DC\SOPHIA\Reader\Files\DC_READER_LAUNCH_CARD
- C:\Users\<USER>\AppData\Local\Adobe\Acrobat\DC\SOPHIA\Reader\Files\ACROBAT_READER_MASTER_SURFACEID
- C:\Users\<USER>\AppData\LocalLow\Adobe\Acrobat\DC\ReaderMessages-journal
- C:\Users\user\AppData\LocalLow\Adobe\AcroCef\DC\Acrobat\Cache\Code Cache\js\05349744be1ad4ad_0
- Local\SyncServiceThread
- Local\Acrobat Instance Mutex
- Global\MSILOG_2743e9d11dbc757GOL.01e21ISM_pmeT_lacoL_ataDppA_onurB_sresU_:C
- Local\SessionImmersiveColorMutex
- Global\AdobeCrashProcessorLocalLowLock
Files this sample writes at runtime
This file drops 10 children at runtime. None are currently flagged malicious in our cache.
- eacad3e01b8b0a44ac03…df796dNever scannednever seen before
- 513fb5d3b4195ab59af2…64de2eNever scannednever seen before
- ad27039abac3252c3b39…37ede5Never scannednever seen before
- 8be39f59f0ffea862a71…e87b4dNever scannednever seen before
- 81ff65efc4487853bdb4…7c8e06Never scannednever seen before
- 9d0035a01f85776e9803…25b7f1Never scannednever seen before
- e3b0c44298fc1c149afb…52b855Never scannednever seen before
- c2995860802b39fc83c8…455702Never scannednever seen before
- 71a8a3976291cdf1f33b…8f0519Never scannednever seen before
- e6cf71c233625c5ee83d…6531eaNever scannednever seen before
Detection & Forensics
Consensus, attribution, signatures, code structure, prevalence, and identity.
Evidence integrity
Chain of custody for the facts preserved in this report.
- 3rule hits recorded
- 0 / 75engines flagged
- 18sources in submission history
Why these facts are shown
Each statement identifies whether it was directly recorded or derived from saved scan facts.
- 01
1 high-confidence signature or behavior rule matched this file.
Verdict inputView chapterProvenanceDerivedSourceSignature and behavior rulesObserved at - 02
0 of 75 antivirus engines flagged the file.
ProvenanceObservedSourceAntivirus analysisObserved at - 03
The hash has been submitted 21 times from 18 sources.
ProvenanceDerivedSourceSaved report factsObserved at - 04
Scanned file: The C Programming Language, 2nd Edition_2#.pdf — adff5d5cba6e961898aaa35727c9f27e1f77df7b127b974cc62ceaa4d1b11623
ProvenanceObservedSourceUploaded fileObserved at - 05
Observed process — C:\Windows\System32\mobsync.exe -Embedding
ProvenanceObservedSourceIsolated runtime analysisObserved at - 06
Observed process — "C:\Program Files\Adobe\Acrobat DC\Acrobat\Acrobat.exe" "C:\Users\<USER>\Desktop\document.pdf"
ProvenanceObservedSourceIsolated runtime analysisObserved at - 07
File written: acroNGLLog.txt — C:\Users\<USER>\AppData\Local\Temp\acroNGLLog.txt
ProvenanceObservedSourceIsolated runtime analysisObserved at - 08
File written: NGL — C:\Users\<USER>\AppData\Local\Temp\NGL\
ProvenanceObservedSourceIsolated runtime analysisObserved at - 09
Contacted host: 23.220.188.152 — Contact observed during runtime.
ProvenanceObservedSourceIsolated runtime analysisObserved at - 10
Contacted host: 23.208.129.2 — Contact observed during runtime.
ProvenanceObservedSourceIsolated runtime analysisObserved at
Detection sources at a glance
The available sources did not agree on a named threat category.
MalwareBazaar, YARAify, and CIRCL hashlookup completed and returned no entries for this hash.
Signatures and behavior heuristics
A community signature or high-severity behavioral heuristic matched. Signatures identify known patterns; heuristics are strong leads but are not proof on their own.
The saved runtime evidence maps this activity to MITRE T1055 (Process Injection). The mapping supports possible process injection, but it does not prove the exact injection method or the operator's intent.
EvidenceC:\Windows\Explorer.EXESandbox observed process activity targeting LSASS (Windows credential store). Legitimate software has no business reading LSASS memory — this is Mimikatz-shape behaviour.
EvidenceC:\Windows\system32\lsass.exeThe sample contacted an external IP address directly and no application domain was recorded. Direct-IP traffic also occurs in legitimate installers and infrastructure, so this is supporting context only and requires corroboration from host reputation and other runtime evidence.
Evidence23.220.188.152 · 23.208.129.2 · 104.126.120.135
0 of 75 engines flagged this file
View all 75 engine results
PE structure
Not applicablePE structure analysis applies to Windows executable formats, not this file type.
How widely this file has been seen
Moderate prevalence — neither rare nor common. No strong prior applies.
Fingerprint and provenance
- File name
- The C Programming Language, 2nd Edition_2#.pdf
- Format
- Code signing
- Not applicable to this file type
- Size
- 15.9 MB
- Last analyzed
- Sep 23, 2026, 9:01 AM UTC
adff5d5cba6e961898aaa35727c9f27e1f77df7b127b974cc62ceaa4d1b11623Safety & FAQ
Complete recovery guidance and answers for the next decision.
What to do now
We couldn't fully clear this file. Treat it with caution.
- Recovery step 01
Don't open it unless you're certain it came from a source you trust.
- Recovery step 02
Check where you got it — an unexpected attachment or a random download link is a red flag.
- Recovery step 03
If its origin cannot be confirmed, delete this file and use a fresh copy from a trusted source. Get a fresh copy from the original trusted source and verify its exact hash when possible.
- Recovery step 04
If you're still unsure, scan it again in a day or two — detections often catch up on newer files.
Safety FAQ
Direct answers grounded in the saved verdict and evidence in this report.
Is The C Programming Language, 2nd Edition_2#.pdf safe, or is it malware?
What is The C Programming Language, 2nd Edition_2#.pdf?
How many antivirus engines detected The C Programming Language, 2nd Edition_2#.pdf?
What should I do if I already opened The C Programming Language, 2nd Edition_2#.pdf?
How do I remove The C Programming Language, 2nd Edition_2#.pdf?
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Community
Member reviews and reports for this exact file hash.