PDF malware analysis — malicious · 52675d24b3e28538

MALICIOUS

PDF

8.0 KB

MD5: d121d4a929e7f5b240150ae360146260 SHA-1: 1da5e09802946e2894ea6b14fdbb47d4155a1b8a SHA-256: 52675d24b3e285388e8e50e0aceda3de61abbfe1f0a49515713f7567f37fabf3

256 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/JScript T1566.001 Spearphishing Attachment T1204.002 Malicious File

This PDF file contains embedded JavaScript, including calls to eval() and unescape(), which are commonly used to obfuscate malicious code. The critical heuristic 'PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER' indicates a stager mechanism within the annotation subject. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to download and execute a second-stage payload.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER

OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
ClamAV: Pdf.Exploit.Agent-35912 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35912
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
JavaScript action low PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
Embedded JS stream low PDF_JS

PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN

PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js` `7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e`	pdf-javascript-stream	PDF /JS object 7 at offset 0x19F	201 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`deobfuscated.js` `368fed861246de8d81cbb35b27fb6011c3eca196a8432c1263c80b942a4f9361`	deobfuscated-js	PDF JavaScript deobfuscation pass	8145 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).

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