PDF malware analysis — malicious · c422f5b5d5d8acc5

MALICIOUS

PDF

7.8 KB

MD5: ebbf71aade2908e495c0f8dcb1f7a3e4 SHA-1: bebf527a238242f7f36449faee4052435115f3c4 SHA-256: c422f5b5d5d8acc591929ef6d7dc883053e2b75b86f23f9f64ad2ff2afacf3d4

256 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript T1204.001 Malicious Link

The PDF file contains obfuscated JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS_OBFUSCATED_DROPPER', and 'CVE_2007_5659'. The critical CVE-2007-5659 heuristic specifically points to the use of 'Collab.collectEmailInfo' to decode and execute JavaScript from an annotation subject. This JavaScript is designed as a multi-stage dropper, likely to download and execute a further payload. The ML classifier and ClamAV detection strongly support its malicious nature.

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-36086 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
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, 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.
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_obj0006_000.js` `f9b4659beaf681d266cfb5046d495e7b144d406eff72e71ecd4d1451ae25ca11`	pdf-javascript-stream	PDF /JS object 6 at offset 0x143	481 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` `ccd48aa1708f89787ee6af809e51b04b65b4d5360f853400a60c0cf019520706`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A1A	1676 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` `8bf934f21807e960f659dcb35ef75875babda25a6bf896ccfb5335f5e8e8b91f`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x329	5006 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `b472d85fe1f533a8c710f9839ee938d9e91abd81683bed53338a00c417a1d6f8`	deobfuscated-js	PDF JavaScript deobfuscation pass	22297 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).

Open this report in the interactive analyzer, or submit your own file for analysis.