PDF malware analysis — malicious · 4a19e16d5bc1aca6

MALICIOUS

PDF

8.1 KB

MD5: e9fb9dc588fd64f0ccd6866dd18a250f SHA-1: 069d37f9c78490930e2a451c0fe2c19f4c7f9226 SHA-256: 4a19e16d5bc1aca67c46bbfd28cfd4569edc55f6d77ff389e5a48f6a0b418797

224 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.001 Malicious Link

The PDF sample contains obfuscated JavaScript, identified by multiple heuristics including 'PDF_JS_OBFUSCATED_DROPPER' and 'CVE_2007_5659'. The JavaScript is designed to download and execute a second-stage payload. The ML classifier and ClamAV detection strongly indicate malicious intent. The primary attack vector appears to be exploiting a PDF vulnerability to achieve remote code execution.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659

PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
ClamAV: Pdf.Exploit.Agent-35916 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35916
Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, 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 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `6c41320119e160dc719997b9a2efb3600ea9d7e9d7e44b4dc2125762dc9f365f`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	505 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` `ad44b13bb4caf3b6ad90d9bd232c3e19278a50cfc4eab2e365e28af93e4417e4`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1B6B	1821 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_001.js` `816d79e6691942675f6ddd0107fb64ce93bf001b8f7fbe9264836e9cff12197e`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x355	5124 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `087932e3b8219545c5c87825588f83c88efae3d0bb9549b9b60c41fd6ff6b893`	deobfuscated-js	PDF JavaScript deobfuscation pass	25807 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 7 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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