PDF malware analysis — malicious · 5104db8aa93cc240

MALICIOUS

PDF

8.2 KB

MD5: d2b5890a4f077eef5ee89b56a90a21cb SHA-1: 5c46caaed6a1f2481832ad9b586fa9fc0b7e31e9 SHA-256: 5104db8aa93cc24071270dd4de3f0dfec3a9ecab155ea5e2256667d2b7c70647

134 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious Link T1071.001 Web Protocols

The PDF contains obfuscated JavaScript, identified by heuristics like PDF_JAVASCRIPT, PDF_JS_OBFUSCATED_DROPPER, and CVE_2007_5659. The script is designed to decode and execute a payload, likely downloading a second-stage malicious file. The CVE-2007-5659 technique involves exploiting a vulnerability to execute arbitrary code, and the presence of multiple deobfuscated JavaScript files indicates a multi-stage attack. The primary IOC is the exploit technique itself.

Heuristics 7

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)
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 4

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` `45194ac35fed24a3a02827e2386324717098c0679ffe43f6d3fcc77737e71c2d`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1BB8	1827 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` `faafefd971b11acf6bef288f2f0b83388e4dd3292b326ffe5d8ef6c6d168fc7f`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x374	5076 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `2bde6980d08adbae2e307eb7e0cb13017822dbb5c728d8acffead7d9f4085a0e`	deobfuscated-js	PDF JavaScript deobfuscation pass	39964 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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