Malicious PDF — malware analysis report

Static analysis result for SHA-256 a757aee1a57e251a…

MALICIOUS

PDF

38.4 KB Created: 2020-04-09 10:51:47 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6) First seen: 2020-09-24
MD5: a8120199984acffbdbc8723fbdce1a4a SHA-1: 8aeb9474b0a9a54f77b33a19a7b1ff0691dafbb0 SHA-256: a757aee1a57e251a8d42bd40a82203838f726b26710b45a0485c763adcd541f6
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The PDF file contains a large number of external links to other PDF files hosted on various domains, a technique often used for SEO link farming or to redirect users to malicious content. The ML classifier strongly indicated maliciousness. The embedded URLs suggest a campaign focused on distributing content through a network of compromised or controlled websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 4

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://asphaltpaverschicagoil.com/uploads/1/3/0/5/130539455/130539455.html#encuesta+de+evaluacion+docente+fes+acatlan PDF link annotation
    • http://enads.org/uploads/1/3/0/5/130540209/d6a5c.pdfIn PDF document text
    • http://poweryourcore.com/uploads/1/3/0/6/130639632/likapila_zurakeje_razusizonam.pdfIn PDF document text
    • http://cheerage.com/uploads/1/3/0/3/130379377/gemox_nufaloga_bizoves.pdfIn PDF document text
    • http://pickapropandposephotobooth.com/uploads/1/3/0/8/130814349/4253520.pdfIn PDF document text
    • http://limonlimonero.com/uploads/1/3/1/4/131408178/donasudum.pdfIn PDF document text
    • http://surfcampcotejax.com/uploads/1/3/1/4/131437484/vitasasokebo.pdfIn PDF document text
    • http://lakecumberlanddiscount.com/uploads/1/3/0/5/130543045/gezitok.pdfIn PDF document text
    • http://princessndow.com/uploads/1/3/0/6/130605217/4062576.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005691.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5691 8560 bytes
SHA-256: 0666261122053c3d87ca2a354d38c4008a90596700f92b4c4e237fa901823c96
font_01_sfnt_off000075db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x75DB 16036 bytes
SHA-256: f335bbb8769c533cbca16f6384a9be7e2e65528b9693bf598f9b6a21ed261b2e