PDF malware analysis — malicious · b14ab47a33965a86

MALICIOUS

PDF

18.2 KB

MD5: 82da31e1cd68c14c31a5df38a285f45d SHA-1: aefc7b636a3a43a3d40da94929de9dbed9d2fcae SHA-256: b14ab47a33965a862d92f1c511b3fe3897cbfd04634fa90729b9011b69a462cd

134 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF file contains obfuscated JavaScript, identified by multiple PDF-specific heuristics including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_JS_OBFUSCATED_DROPPER'. The 'PDF_JS_OBFUSCATED_DROPPER' heuristic indicates that the script is designed to act as a multi-stage dropper, likely downloading and executing a second-stage payload. The ClamAV detection 'Pdf.Exploit.Agent-35901' further confirms the malicious nature of the file. The obfuscated nature of the script and the lack of specific indicators for a known family lead to an 'unknown family' classification.

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 3

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 0x4630	469 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `028ecafd16c8acf4c560a5ae46f4db05b5acd0f369ad7f4049af026f8bb9aa67`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1BAA	11978 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`deobfuscated.js` `13052fc05b0942da24fa564d961dd95a7dab079d4e6879761365258c108a62f3`	deobfuscated-js	PDF JavaScript deobfuscation pass	157251 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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