PDF malware analysis — malicious · b77d8f0257e2df81

MALICIOUS

PDF

17.6 KB Created: 2010-08-29 16:19:36 Authoring application: styeZek colSnap

MD5: dc418caf6348f8768630c70155551a86 SHA-1: bc9e4485ac2b7884aeb1dcfc6e3489b32e36be04 SHA-256: b77d8f0257e2df818acb08385f716d51fcc54cd7ac59bc421206d3f6c575c251

216 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF sample exhibits high-confidence heuristic firings for embedded scripts and XFA form exploitation, strongly indicating malicious intent. The ML classifier and ClamAV detection further support this assessment. The presence of embedded files and the PDF_EVAL heuristic suggest the document is designed to execute arbitrary code, likely to download and run a second-stage payload. The specific nature of the payload is not discernible from the provided evidence, but the overall pattern points to a downloader or dropper.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

Heuristics 9

XFA form contains risky executable script high CVE related PDF_XFA_SCRIPT

PDF embeds an XFA form whose script block contains exploit, submission/launch, or shell-execution primitives. Ordinary LiveCycle print/update scripts are left as generic XFA/JS signals unless stronger behavior is present.
ClamAV: Pdf.Exploit.Dropped-81 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Dropped-81
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD

PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
XFA form low PDF_XFA

PDF uses XML Forms Architecture — can contain script logic
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)
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://ns.adobe.com/xdp/
- http://www.xfa.org/schema/xci/1.0/
- http://www.xfa.org/schema/xfa-form/2.8/

Extracted artifacts 7

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`embedded_file_obj0008.bin` `d81baa73e490e4cb879e13927cacd1dd1be37524a37eac51603e15117c578777`	pdf-embedded-file	PDF EmbeddedFile object 8 at offset 0xDB	84 bytes
`embedded_file_obj0009.bin` `24c130f03a4cf51d470b536e94c1e58af67665739e200e0ce198ad41086243c0`	pdf-embedded-file	PDF EmbeddedFile object 9 at offset 0x176	228 bytes
`embedded_file_obj0010.bin` `5deebd98fcfdd4891f35a0afcfb2b5303fd447f7e632c296b1b403eb75612221`	pdf-embedded-file	PDF EmbeddedFile object 10 at offset 0x2B8	975 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`embedded_file_obj0011.bin` `c97e0522381d6196cc0695f35f4d065f15c9c86a9601a7f776c6afd3f4c6b460`	pdf-embedded-file	PDF EmbeddedFile object 11 at offset 0x535	199 bytes
`embedded_file_obj0012.bin` `a8e48b52b99e0ef58cb63f5eaa9a114a289ce1911ee80a2468c5df4f7afdf517`	pdf-embedded-file	PDF EmbeddedFile object 12 at offset 0x627	34734 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`embedded_file_obj0013.bin` `e6c26a3478346d27e841ad49868ebf68bf4c6863b6750e8d60bda3c4c6f79876`	pdf-embedded-file	PDF EmbeddedFile object 13 at offset 0x41C1	77 bytes
`embedded_file_obj0014.bin` `92a3ce61d783e15932b5de127ce45a9b4c2f98f4da2453f65241573c1dda808a`	pdf-embedded-file	PDF EmbeddedFile object 14 at offset 0x4254	56 bytes

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