PDF malware analysis — malicious · f3b71c92c83f7fee

MALICIOUS

PDF

7.9 KB

MD5: ee43f0d5e70b4252b661737bef70ecbc SHA-1: 5285a6c5cd73c5047158d9d3f9dd4a883ee784e7 SHA-256: f3b71c92c83f7fee1983b01311c832e9513e492ff274f2044924f6cd95d944dd

194 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF document contains obfuscated JavaScript that leverages the CVE-2007-5659 vulnerability. This script is designed as a multi-stage dropper, indicated by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. It decodes a hex-dashed payload and uses String.fromCharCode to build and execute further stages, ultimately leading to the download and execution of a malicious payload. The ClamAV detection 'Pdf.Exploit.Agent-35916' further confirms its malicious nature.

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` `6477df9b5e67db15afa2b24767f18587ea8334557efff0c1a82aad2517ccfee6`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A6E	1826 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` `2fe27c3930c48dab99fd210f6c9a599173bc1a4c6836520b43ccd04f5c16798c`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x352	4835 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).
`deobfuscated.js` `a1d62a0f06b4ab1d516ee3749d88a8557cb0a1326c5346bfbbeea6c76d6eacfa`	deobfuscated-js	PDF JavaScript deobfuscation pass	22932 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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