PDF malware analysis — malicious · 2d957bdf8fcca9a3

MALICIOUS

PDF

8.2 KB

MD5: 2d564bce2d0ed6d5a3c5d19eb1daa6e4 SHA-1: 1ee7f4c6c87471a88f45bb28601b86f0aae39c76 SHA-256: 2d957bdf8fcca9a3d3c41823b85c0bb5fcaa6d33d61a1ee4993caf65c4ca65a4

316 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1566.002 Spearphishing Attachment T1204.002 Malicious File

This PDF file contains obfuscated JavaScript, as indicated by multiple PDF_JAVASCRIPT and PDF_JS heuristic firings. The critical CVE_2007_5659 heuristic specifically points to the use of the Collab.collectEmailInfo method to decode and execute JavaScript from an annotation subject. The ML classifier and ClamAV detection further confirm its malicious nature, identifying it as Pdf.Exploit.Agent-36086. The primary attack vector appears to be exploiting a known PDF vulnerability to deliver a malicious payload.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 9

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
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
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` `0eff7fbc7087747fb1fefcf50cccc21956ff3e38c66c11fc699f196b88654e9e`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1B93	1800 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_001.js` `4d1788953f7e48a3ccaed19e6fec529e713efd1f9c3991f43c79c7ae2f9941b4`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x329	5127 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `444f96f239ada88b70499187ae7f36cb7809b977ef12cc8aec2b3c9583159d11`	deobfuscated-js	PDF JavaScript deobfuscation pass	42784 bytes
Detection ClamAV: Pdf.Exploit.Agent-36086 Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).

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