Malicious PDF — malware analysis report

Static analysis result for SHA-256 66d6c4cb53a4841f…

MALICIOUS

PDF

75.0 KB Created: 2020-06-04 14:11:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f83df6d765677102c7c31864b24ffb97 SHA-1: 0d4e805fb7c1c4bab72a2c3b593434b256619451 SHA-256: 66d6c4cb53a4841f87d3fd8b09e131d5367de779c6248e8095a3dda34f3e04d9
96 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded external links, a technique often used for SEO spam or to redirect users to malicious sites. The ML classifier strongly indicated maliciousness, and the PDF_SEO_LINK_FARM heuristic confirms the presence of a link farm. While no scripts were explicitly extracted, the embedded URLs are the primary indicators of malicious intent, likely serving as a distribution point for further malware or phishing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://3kg.undesirable.us/uploads/1/3/0/8/130874593/130874593.html#%25D9%2582%25D8%25B5%25D8%25B5+%25D8%25AC%25D9%2586%25D8%25B3+%25D8%25AC%25D9%2585%25D8%25A7%25D8%25B9%25D9%258A%25D8%25A9+%25D9%2586%25D8%25A7%25D8%25B6%25D8%25AC%25D8%25A9
    • http://willfredogerardo.com/uploads/1/3/0/3/130379634/be199922393cd.pdf
    • http://beckymk.pink/uploads/1/3/1/4/131455416/bakitirolerumu-kurutejuz-parezexa-menonab.pdf
    • http://cuiwenqing.com/uploads/1/3/0/7/130775879/90ea8.pdf
    • http://mx.heritagesdachurchnyc.org/uploads/1/3/0/5/130589302/kutokafudebil.pdf
    • http://3kg.undesirable.us/uploads/1/3/0/8/130874593/terms.html
    • http://3kg.undesirable.us/uploads/1/3/0/8/130874593/dmca.html
    • http://3kg.undesirable.us/uploads/1/3/0/8/130874593/policy.html
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://juzifotexi.files.wordpress.com/2020/06/basomaziwaxojesasimer.pdf
    • https://tukevorigo.files.wordpress.com/2020/06/vuzovuvufavotizifani.pdf
    • https://faxirena.files.wordpress.com/2020/06/roxavawoxosiwoza.pdf
    • https://rufofuvokije.files.wordpress.com/2020/06/96073713689.pdf
    • https://xulesik.files.wordpress.com/2020/06/ritibubuwitomilure.pdf
    • https://lopulonemeji.files.wordpress.com/2020/06/12161076533.pdf
    • https://lavoxujes.files.wordpress.com/2020/06/ligenewolibalunomurogis.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_002_off0000c7f4.bin
8f9da4ee74f9020f6df85acf672fef791f398c6e2943b907e4845eaf3f0507e6
decompressed-pdf-stream PDF FlateDecoded stream at offset 0xC7F4 32512 bytes
font_01_sfnt_off00010011.bin
3ff6c3eee32c7ce342c395af9207c687f9e2244e9bedbaecec12657c2f065de9
pdf-font-stream PDF embedded font (sfnt) at offset 0x10011 8804 bytes