Malicious PDF — malware analysis report

Static analysis result for SHA-256 923d9990be41d7c2…

MALICIOUS

PDF

43.4 KB Created: 2020-04-02 08:16:57 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: f794063b0665b572fc4d1c245595437f SHA-1: 4436ac73aea6c473ef9a0e0fec6a1d2735920d43 SHA-256: 923d9990be41d7c2e3c5a39a0deb36b851ec925e5822b3dd380fe80203da955a
94 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of external links, many with numeric slugs, indicative of a link farm or SEO poisoning tactic. The document body, though partially corrupted, contains text related to probability exercises and references the wkhtmltopdf tool, suggesting a deceptive lure. The ML classifier strongly flagged this PDF as malicious, and the presence of numerous unknown-reputation URLs reinforces the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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://sinkincreek.com/uploads/1/3/0/6/130622075/130622075.html#ejercicios+de+la+regla+de+la+multiplicaci%C3%B3n+probabilidad+conjunta+y+probabilidad+condicional
    • http://hostmaster.thecostumepartyshop.com.au/uploads/1/3/1/3/131379447/8335869.pdf
    • http://specialfxstyle.com/uploads/1/3/0/6/130604114/zoluluzalunigugu.pdf
    • http://safedesignsolutions.com/uploads/1/3/0/7/130739951/jopilaguf.pdf
    • http://tolhouse-design.com/uploads/1/3/0/6/130604657/6162903.pdf
    • http://startingblockhomes.com/uploads/1/3/0/7/130739783/a44488508488.pdf
    • http://rmclasssites.com/uploads/1/3/0/7/130740497/dilukarobupumijosit.pdf
    • http://mhayemonti.com/uploads/1/3/0/3/130313536/tipewivigozepigi.pdf
    • http://sujitbehera.com/uploads/1/3/0/6/130603842/18c8becfbc.pdf
    • http://500chipeta.com/uploads/1/3/0/7/130775596/daperodob.pdf
    • http://www.freedom-cs.com/uploads/1/3/1/3/131383469/125403.pdf
    • http://gacsalyi.net/uploads/1/3/0/2/130289392/149bb3d81be503a.pdf
    • http://bitbybittraining.com/uploads/1/3/0/5/130590475/4466036.pdf
    • http://coinsofthetrade.com/uploads/1/3/1/4/131437352/luwuvoxoveladu.pdf
    • http://myadaptivehomesolutionsllc.com/uploads/1/3/0/2/130289184/7871419.pdf
    • http://markthalle93.ch/uploads/1/3/0/7/130738673/4900230.pdf
    • http://runningonsprinkles.com/uploads/1/3/0/2/130271083/giborewalegag.pdf
    • http://destinationdancesb.com/uploads/1/3/0/7/130740133/derabevuwo-gelexemunu.pdf
    • http://onlinewerkenmeerverdienen.nl/uploads/1/3/0/5/130588586/1344135.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/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000796d.bin
3f1daa99fd3a279c29ae93cb439e40d0fc237d93149953b521647f4e640c5eea
pdf-font-stream PDF embedded font (sfnt) at offset 0x796D 9428 bytes