PDF malware analysis — malicious · ec7761ded2e89685

MALICIOUS

PDF

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

MD5: fcee8dd48c891389d7134159779382a4 SHA-1: 08276129ea694c23d59d4b4f4baf2a807bc86a55 SHA-256: ec7761ded2e89685e3f80d3c61a99f21038be7437f72880cb135c4ec2b32cec7

216 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is a PDF document flagged by ClamAV as Pdf.Exploit.Dropped-81. High-severity heuristics indicate the presence of risky executable script within an XFA form, including eval() calls and String.fromCharCode usage. These scripts are likely responsible for downloading and executing a second-stage payload, as suggested by the embedded file artifacts and the ML classifier's high confidence score. The specific URLs extracted are related to XFA schema definitions and are not directly indicative of malicious infrastructure.

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` `425709f560aec6ea5c75dd212a882b8f63d3b2c5e6b749198024bdfc77803d5f`	pdf-embedded-file	PDF EmbeddedFile object 10 at offset 0x2B8	966 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 0x532	199 bytes
`embedded_file_obj0012.bin` `2bcfef3c658ee833ce145bfea770ff3b0d20b923f840a57393b116ff191b0024`	pdf-embedded-file	PDF EmbeddedFile object 12 at offset 0x624	34710 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 0x41B0	77 bytes
`embedded_file_obj0014.bin` `92a3ce61d783e15932b5de127ce45a9b4c2f98f4da2453f65241573c1dda808a`	pdf-embedded-file	PDF EmbeddedFile object 14 at offset 0x4243	56 bytes

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