PDF malware analysis — malicious · 4c0a129e72f4a44c

MALICIOUS

PDF

17.5 KB

MD5: 2b628efc3adc0a0e24e979f70a03b8ae SHA-1: 3b9fd29d8e412c15db162c1d39d1a0e3605f43bb SHA-256: 4c0a129e72f4a44ce0add6663f5981946c570a41d81ff1e029a8e32ee7336267

134 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, identified by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. This script is designed to decode and execute a payload, likely from an embedded resource or an external URL. The presence of 'String.fromCharCode' and incremental evaluation further indicates a multi-stage attack. ClamAV detection as 'Pdf.Exploit.Agent-35901' confirms its malicious nature.

Heuristics 7

ClamAV: Pdf.Exploit.Agent-35901 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 4 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, incremental_eval_build, 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.
String.fromCharCode low PDF_FROMCHARCODE

String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
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_obj0009_000.js` `4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d`	pdf-javascript-stream	PDF /JS object 9 at offset 0x436E	469 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`deobfuscated.js` `1aad0fd1e44d22bd705c227198ba9753a10ff800bcf6695f6fb8501e99e2eb0b`	deobfuscated-js	PDF JavaScript deobfuscation pass	162122 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).

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