Malicious PDF — malware analysis report

Static analysis result for SHA-256 320c3e5fa5454b54…

MALICIOUS

PDF

9.8 KB Authoring application: %title%
MD5: c432a75b77eb360a599d274283d8b8b8 SHA-1: e7788bc091d46fa4e3acabb1ec08d7c23abf7cfa SHA-256: 320c3e5fa5454b548877480b5e0faec85da8ba7476b6b2e487a1eda12d259144
176 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious Attachment T1566.002 Phishing: Spearphishing Attachment

The critical ClamAV detection and ML classifier output strongly indicate this PDF is malicious. It contains embedded files, one of which was also flagged by ClamAV. The presence of an XFA form and an AcroForm button with an action trigger suggests an exploit is being leveraged to execute embedded content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-36962 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36962
  • 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.
  • 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
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • 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://www.xfa.org/schema/xfa-locale-set/2.1/

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0041.bin
c06dcd026a7ea0536b63e07ce688691b585339a3ab7ff59065e546b56308c7bb
pdf-embedded-file PDF EmbeddedFile object 41 at offset 0x111A 85 bytes
embedded_file_obj0042.bin
dda0835df994b8be920f715db36452f6cee7bb42bbc9c897f878a7b298ba8e91
pdf-embedded-file PDF EmbeddedFile object 42 at offset 0x11CC 1029 bytes
embedded_file_obj0043.bin
fa20becb44ef00d7e501ae24d90dd16fdf19529a6b4d87d45834dde6d6e99d5d
pdf-embedded-file PDF EmbeddedFile object 43 at offset 0x13E5 8294 bytes
Detection
ClamAV: Pdf.Exploit.Agent-36962
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
embedded_file_obj0044.bin
3dd68f00f4fcb366a2a3a17c65cb2626eeddf5ea5713302d374310561d810169
pdf-embedded-file PDF EmbeddedFile object 44 at offset 0x23E8 144 bytes
embedded_file_obj0045.bin
10c03f88a5f0a0833dc5b2c8ac295b3a3c6f65e23889eb8cc1dc6fe29bf7f275
pdf-embedded-file PDF EmbeddedFile object 45 at offset 0x2494 77 bytes