PDF malware analysis — malicious · f8c537d0a2698340

MALICIOUS

PDF

7.8 KB

MD5: edfe59041cfbbd65e0b7a8f03a043900 SHA-1: cfdfc48c1b10d75fab023420db9aae162852e7ba SHA-256: f8c537d0a2698340d2ad0f27793e2a02fc041faedb74e83fb393759422c81fc3

316 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF document exploits CVE-2007-5659, leveraging JavaScript embedded within annotations to execute malicious code. Heuristics indicate an obfuscated multi-stage dropper that decodes and evaluates JavaScript. The extracted JavaScript files, particularly 'deobfuscated.js', are likely responsible for downloading and executing a second-stage payload, as suggested by the 'PDF_JS_OBFUSCATED_DROPPER' and 'ML_NYX_PDF_MALICIOUS' firings. The ClamAV detection further confirms its malicious nature.

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` `a49a704140c2384e217c9f2bfb031602def10b58d85dbc25799d362b9c7b58db`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1A69	1627 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` `0cfd3c42ddd1fdfafa90ab56fc99947a9e6a6841b51a9871bbc2632bd52af5fe`	deobfuscated-js	annotation-subject callee-key decoded JavaScript at offset 0x329	4911 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`deobfuscated.js` `b1d71d76dc0e8dc620344a29ab28d61aecfd14c11beb85d494b63021b9c22bec`	deobfuscated-js	PDF JavaScript deobfuscation pass	34993 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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