Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b6dd491596d5880…

MALICIOUS

PDF

70.4 KB Created: 2020-06-05 20:46:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 8638b78b0e61be2b82487af507bc57a5 SHA-1: 4ce1b5e425f01a9a711a1e99905f2e9c25a85817 SHA-256: 5b6dd491596d58807602d3fb55c9fe36c76f5270b53d6690fc861a4a68dc84df
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a large number of external links, many of which point to other PDF files with numeric slugs, indicative of a link farm. The ML classifier strongly flagged this PDF as malicious, and the presence of embedded URLs further supports malicious intent. While no scripts were explicitly extracted, the PDF structure and numerous external links suggest an attempt to manipulate search engine results or redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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://kelbels.org/uploads/1/3/0/6/130620363/130620363.html#how+to+pray+salat
    • http://valleyroadvineyard.com/uploads/1/3/0/6/130620436/nafoxivirudomo.pdf
    • http://southboundboutiqueco.com/uploads/1/3/1/6/131636697/suzox.pdf
    • http://sayuriyakitori-llc.com/uploads/1/3/0/5/130588813/7a38cf33.pdf
    • http://kozowski4sheriff.com/uploads/1/3/0/9/130969194/7760959.pdf
    • http://bridge33.net/uploads/1/3/0/3/130323471/kasonokugamur_wegigorake_xukawotow.pdf
    • http://belletravels.com/uploads/1/3/1/4/131407082/5339343.pdf
    • http://energizeyourintentions.net/uploads/1/3/1/3/131398294/peroz.pdf
    • http://mx.shipinbottles.com/uploads/1/3/0/7/130739128/9ff20547276084f.pdf
    • http://hostmaster.pccurryflooring.com/uploads/1/3/0/5/130551696/nevujapepinure_sanejizuwojuti_zinix.pdf
    • http://kelbels.org/uploads/1/3/0/6/130620363/terms.html
    • http://kelbels.org/uploads/1/3/0/6/130620363/dmca.html
    • http://kelbels.org/uploads/1/3/0/6/130620363/policy.html
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://banisozix.files.wordpress.com/2020/06/zasikawujikaluvozar.pdf
    • https://turoxox.files.wordpress.com/2020/06/9774657122.pdf
    • https://kopidofawu.files.wordpress.com/2020/06/13618471630.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0000e986.bin
57732eaa82f257abaa9f60f8c0c9c6ed15861315f51bbe08ef3412d7b83480aa
decompressed-pdf-stream PDF FlateDecoded stream at offset 0xE986 21140 bytes
font_00_sfnt_off0000c258.bin
0e5223a8920c4a0f43b27c477c65577dc857e0fbb31348c141510743d0b299e8
pdf-font-stream PDF embedded font (sfnt) at offset 0xC258 11444 bytes