PDF malware analysis — malicious · d3130ebe44f97a98

MALICIOUS

PDF

15.5 KB

MD5: c3289e679eb8a3427de7e50eba5c414b SHA-1: 57cc0fecd9a483180bcf05d104f305a505334c36 SHA-256: d3130ebe44f97a98044249cf4ddc59467c9620edcf2271190d5a51c9d0b96910

74 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 act as a multi-stage dropper, likely downloading and executing a second-stage payload. The presence of multiple embedded JavaScript files and the 'String.fromCharCode' usage further indicate a complex, obfuscated delivery mechanism. The exact nature of the second-stage payload could not be determined due to the obfuscation, but the overall pattern suggests a downloader.

Heuristics 6

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.
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_obj0005_000.js` `ab3f4be7a3e2e879e844dcace56ca59cf8fe7249dc5a05c90896f0c9e7dd732a`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	559 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `702f927077f1daf86eb49a73e227b1a6c6c4fe64039e27be48c4672395d8d640`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A8A	11677 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` `57cd20f9befb9c602e425884c24eb9f005dfbbb7dab246a67c6166a5e94c84db`	deobfuscated-js	PDF JavaScript deobfuscation pass	59214 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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