Malicious PDF — malware analysis report

Static analysis result for SHA-256 55bd8e4863da900c…

MALICIOUS

PDF

6.3 KB Created: 2010-08-29 16:19:36 Authoring application: styeZek colSnap
MD5: 2f80d9e2adfbf3fe57cdbb02eac75001 SHA-1: f99de999423de0a10ab18fa0d2f87d847c76c478 SHA-256: 55bd8e4863da900c8fc47f92034cd4b85150cfb7fa5c42f95858a897876bea40
216 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.001 PowerShell

This PDF file exhibits multiple high-severity heuristic firings, including PDF_EVAL and PDF_XFA_SCRIPT, indicating the presence of executable script within an XFA form. The ML classifier strongly flags it as malicious, and ClamAV identifies it as Pdf.Exploit.Dropped-81. The presence of embedded files, specifically 'embedded_file_obj0011.bin' and 'embedded_file_obj0014.bin', suggests these are likely payloads. The script's purpose is to download and execute a second-stage payload, leveraging the embedded files.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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
  • 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-template/2.5/
    • http://ns.adobe.com/xtd/
    • http://ns.adobe.com/xfdf/
    • http://www.xfa.org/schema/xfa-form/2.8/

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin
78f9631071f03cd2eafd8de565f399d0c62edde5175ed6f90c6215135b7f3b76
pdf-embedded-file PDF EmbeddedFile object 8 at offset 0xDB 134 bytes
embedded_file_obj0010.bin
d4ff871de6628873a7035e48c3dfa9affd8413c4e514b4f2b79a912efb0ddaf9
pdf-embedded-file PDF EmbeddedFile object 10 at offset 0x1AA 712 bytes
embedded_file_obj0011.bin
8ce253bca468d2aadd545fac249e9c406f172b477d323e3dda98dfea79ec1de6
pdf-embedded-file PDF EmbeddedFile object 11 at offset 0x4BD 444 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
embedded_file_obj0012.bin
103d1e7983cf88bfacedddb4af33ffb5317d9c2c8b3e1bfd987b2c5d712bc985
pdf-embedded-file PDF EmbeddedFile object 12 at offset 0x6C4 323 bytes
embedded_file_obj0014.bin
23b41ae7a30f1e8d2278d6f53c13d6eb9fe4bc02f807888c4b2b3bbe6fd06c76
pdf-embedded-file PDF EmbeddedFile object 14 at offset 0x865 12298 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 4 long base64-like blob(s).
embedded_file_obj0015.bin
e6c26a3478346d27e841ad49868ebf68bf4c6863b6750e8d60bda3c4c6f79876
pdf-embedded-file PDF EmbeddedFile object 15 at offset 0x14BA 77 bytes
embedded_file_obj0016.bin
92a3ce61d783e15932b5de127ce45a9b4c2f98f4da2453f65241573c1dda808a
pdf-embedded-file PDF EmbeddedFile object 16 at offset 0x154E 56 bytes