PDF malware analysis — malicious · c2440990c04f9d3f

MALICIOUS

PDF

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

MD5: 385e4f89595030178dc2871e0f001f1a SHA-1: 0162766e191ad35a643976bc855d026977c6343d SHA-256: c2440990c04f9d3fc33830482d1f8499b4ba10be92084bcc0f53d7f4c65b3e2b

216 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF file was flagged as malicious by ClamAV with the signature Pdf.Exploit.Dropped-81. High-severity heuristics indicate the presence of risky executable scripts within an XFA form, including eval() calls and embedded script payloads. The ML classifier also strongly indicated maliciousness. The primary attack vector appears to be exploiting a PDF vulnerability to execute a script, which likely downloads and executes a second-stage payload.

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` `542b336aa2fdc77899cea0027208b2b8960805cebe9e75ef32234f716c6da7f9`	pdf-embedded-file	PDF EmbeddedFile object 10 at offset 0x2B8	976 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 0x533	199 bytes
`embedded_file_obj0012.bin` `0b03b58a0fb81b9523004cb909ee43cec460dae5c1cec814d74d877554f250fe`	pdf-embedded-file	PDF EmbeddedFile object 12 at offset 0x625	34213 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 0x40F5	77 bytes
`embedded_file_obj0014.bin` `92a3ce61d783e15932b5de127ce45a9b4c2f98f4da2453f65241573c1dda808a`	pdf-embedded-file	PDF EmbeddedFile object 14 at offset 0x4188	56 bytes

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