PDF malware analysis — malicious · f1cb1904986b53a4

MALICIOUS

PDF

15.6 KB

MD5: 16a066edb1160d02e73aa89e896959f1 SHA-1: 35979b1ee17bed361b4a97317fbb8f6ad858fe51 SHA-256: f1cb1904986b53a40ef7b7d2becea4a07d8fc8d746e8ed67077096ec7fd51937

66 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, identified as a multi-stage dropper. This script is designed to download and execute a second-stage payload, as indicated by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. The presence of deobfuscated JavaScript files suggests a complex, multi-stage infection chain.

Heuristics 5

Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `a3319192cac6d4dc4eeb6af2d736b0ffec979b23116a003bc7c23382761c32a5`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	733 bytes
`legacy_pdfkit_stage_000.js` `19f96898b53eac3a4ef9b5958e4ba158a773554eee37165344c6ece83d3d050d`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1AA5	12157 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`deobfuscated.js` `fde722e13e6299ad0c0a0813426c91b73c9cbfb5661925e08d81128bfcaa2d9b`	deobfuscated-js	PDF JavaScript deobfuscation pass	56661 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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